Cholestatin, a phytosterol complex isolated from vegetable oils, is marketed as a dietary supplement and it contains campesterol as a main ingredient [ 33 ].
The squalene concentration in P. It is a naturally occurring carbon organic compound Fig. Squalene is a significant interest in pharmaceutical and cosmetics because of its antioxidant properties, cholesterol lowering effects, protection against coronary heart disease, tumor reduction properties and thus potential anticancer activity [ 34 ]. The proposed mechanism was the inhibition of cell proliferation by decreasing the level of farnesyl pyrophosphate FPP required for oncogene activation. Its antioxidant activity was highlighted by the inhibition of isoprenaline-induced lipid peroxidation and its capability to lower blood cholesterol levels.
In the cosmetics sector, the emollient and hydration properties of squalene possess compatibility with the skin surface lipids. Squalene along with its hydrogenated analog is used for the formulation of varied personal care products such as moisturizing creams, lipstick, nail and hair products [ 34 ]. Anti-nutrient factors either reduce the absorption of nutrients or interfere in further metabolic pathways, thus decreasing the nutrients bioavailability. Anti-nutrients such as tannin, trypsin inhibitor and hemagglutinin are present in low amount in P.
Zaini and Mustaffa [ 16 ] reported that stinky beans contain tannins 0. Huge bioactive potential of stinky beans accounts for the diverse health benefits and thus for the pharmacological properties of the plant [ 5 ]. More vegetable consumption is highly beneficial in terms of various health promoting and protective benefits as compared to fruits [ 35 ]. Traditionally; a rich diet in stinky beans is believed to be useful in the treatment of certain diseases such as diabetes, cholera and kidney pain.
But so far, there has been no scientific evidence to support this [ 36 ]. Several escalating evidence supports the function of hydrogen sulfide H 2 S as a cardioprotective vascular cell-signaling molecule. Hydrogen sulphide, nitrous oxide and carbon monoxide which are entitled as gaso-transmitter exhibit certain important physiological and pharmacological roles. Production of H 2 S is done internally by the action of pyridoxal phosphate-dependent enzyme cystathionine-c-lyase CSE on cysteine in smooth muscle tissues [ 37 ]. Several studies indicate the fact that the H 2 S produced from biological conversion of organosulfides is related to several cardiovascular health benefits which also include vascular smooth muscle relaxation [ 38 ], systolic blood pressure reduction and cardio-protection during myocardial ischemia and acute myocardial infarction [ 39 ].
Lectins have the ability to induce apoptosis through different pathways which are effective in specific cell lines. This can be performed by stimulation of carpases production in the molecular pathway. These pathways are involved in down-regulation or up-regulation of certain genes included in apoptotic suppression or induction, respectively. Certain mRNA behaves as ribosomal inactivating proteins RIPs inhibitor and can be down-regulated through lectin activity which allows the RIPs to function properly and impede neoplastic growth [ 16 ] and thus reduces the chances of cancer. Aiona et al.
Based on the ethnobotanical record of Malaysia, P. Antioxidant potential is strongly correlated with the reduction in risk of various critical diseases of humans such as hypertension, atherosclerosis, diabetes, stress-induced gastric lesion and cancer. Phenolic compounds and flavonoids contribute directly to antioxidative functions as these possess impeding actions on genetic mutation and carcinogenesis in human [ 41 ]. The leaves and seeds of the plants also showed antioxidant activity which was relatively low when compared with the activity in the pod and seed mixture.
This suggests that the pods retain greater antioxidant content than the other parts of the plant. Ayub et al. Udenigwe and Aluko demonstrated that the excess amount of electrons is donated and bonded with free radicals making peptidic amino acids the potent antioxidants [ 43 ]. The radical quenching activities of food antioxidants are attributed towards the ability of the antioxidants to engage in single electron transfer reaction; so the amplitude of peptidic amino acid residues that can transfer electrons to the free radicals at physiological pH can bestow enhanced antioxidative properties [ 43 ].
It was proposed that N-acetyl cysteine operated to scavenge free radicals yielded as a result of endotoxin cascade, but the possibility remained that it might have acted through maintenance of intracellular glutathione levels. Phenols and flavonoids possess the antioxidative properties and are utilized for the formulation of different drugs [ 45 ]. It also possesses cardio-protective effects by reducing angiotensin-converting enzyme activity [ 46 ].
Functional foods are alike conventional foods consumed as part of daily diet and demonstrate physiological benefits along with reduction in chronic diseases along with basic nutritional functions. The species has the potential to produce functional fibers and flour-forming capabilities [ 2 ]. Antioxidants also help in enhancing the shelf life of food, reducing nutritional losses and avoiding the formation of free radicals [ 41 ]. Parkia speciosa pod contains pectin content varied from This makes it a suitable substrate for extraction of colloidal agent pectin for further usage in food industry.
The leguminous plant Fabaceae, contains fibers, vitamins and mineral constituents. In traditional medicine, several parts of plants of the family of Fabaceae are. ykoketomel.ml: Fabaceae: Classification, Nutrient Composition and Health Benefits (Plant Science Research and Practices) (): Wayne Garza.
Pod also contains a good amount of protein 9. The starch content and the fibers could boost texture and gastric health for the consumers since the health food trend in bakery such as whole grain breads and cookies is introduced [ 2 ]. Different antioxidant formulations are being sold as diet supplements by neutraceutical and food companies in industrialized nations [ 48 ]. The pods could be used to produce a high antioxidant polysaccharide that acts as functional carbohydrate in food applications.
Parkia speciosa , as an important source of antioxidant and anti-hypertensive bioactive peptides, could be considered essential in development of natural functional food ingredients. The bioactive peptides were successfully derived from the seeds using the enzyme alcalase. A total of 29 peptide sequences were identified from the peptide fraction [ 49 ]. Food-derived bioactive peptides are distinct protein fragments having beneficial pharmacological properties to human body [ 50 ]. Plant proteins are a necessary constituent for modern food improvements, in particular in nutrition and health [ 49 ].
Fermented food products have a strong association with the culture and tradition of a country [ 51 ]. The functional potential of lactic acid bacteria is evaluated in technological terms and its application is provided in fermented stinky beans. The beans sustain spontaneous fermentation in brine and have its own characteristic flavors and taste. Lactic acid bacteria were isolated from the fermented beans using PCR-denaturant gel gradient electrophoresis and evaluated for its functional characteristics [ 52 ]. The major lactic acid bacteria identified were Lactobacillus plantarum , Lactobacillus fermentum , Lactobacillus pentosus and Enterococcus feacium.
These bacteria along with its probiotic properties can be utilized as a starter culture in the fermentation process. The colonization of probiotic bacteria averts the growth of harmful bacteria through competition exclusion and production of organic acid and anti-microbial compounds [ 52 , 53 ].
Live probiotic Gram-positive bacteria belonging to cocci cell morphology are beneficial for human heath such as decrease of cancer risk, improvement of immune and mucosal barrier system [ 53 ]. Activated carbon has various applications in industry, medicine, environment and agriculture such as solution purification, clarification and adsorption. Activated carbon can be used for removal of off-flavors and odors from domestic and industrial water supply, waste water treatment, clarification and degumming of fats and oils from vegetable and animal sources, and removal of off-flavors and odors from alcoholic beverages [ 54 ].
Commercial activated carbon is a preferred adsorbent for the removal of micro-pollutants. The main purpose is removal of the organic and inorganic compounds from the gaseous and liquid streams [ 55 ]. However, the usage of activated carbon is limited due to its high cost of production and, thus, agricultural wastes are also considered as the potential precursors for activated carbon AC due to low cost and abundant supply. The low ash content and reasonable hardness make agricultural waste a rich source of activated carbon.
Different agricultural wastes of apricot, coconut, sugarcane and corn possess considerable rigidity, such as the shells and the stones and, thus, P. The pod of the plant is used in the development of AC through phosphoric acid activation. There are two methods for AC synthesis viz. The precursor of physical activation is first carbonized and activated in a stream of carbon dioxide. In case of chemical activation, the precursor is impregnated with a dehydrating agent, usually zinc chloride or organic acids prior to carbonization.
However, zinc chloride method increases the environment contamination by zinc compounds and so utilization of phosphoric acid as the dehydrating agent is considered as the safe and effective method [ 56 ]. Artificial colors and dyes used in food industries to manipulate quality may lead to carcinogenicity, hypersensitivity, behavioral effects on prolonged consumption and thus not considered as safe [ 57 ]. The pod extract produces polyphenolic, betalain dye and chlorophyll content which is used in dyeing. It is being used for purposes of dyeing silk fabrics and it produces a natural dying procedure in color fastness and provides UV protection [ 58 ].
Betalain dye present in the pod extracts, when combined with sodium hydroxide, resulted in light brown to yellow dye to shade fabric. Parkia speciosa is a traditionally cultivated and locally consumed crop. The seeds and pods are eaten as a local delicacy in certain parts of the world as raw, cooked or pickled.
These phytochemicals are beneficial in terms of anti-diabetic, anti-microbial, antioxidants, anti-hypertensive and hypoglycemic effects.
Commercial utilization has also begun in exporting department; pharmacological departments as the understanding of the benefits have come to light. So, as a whole, the plant is worth understanding and utilizing. Cholestatin, a phytosterol complex isolated from vegetable oils, is marketed as a dietary supplement and it contains campesterol as a main ingredient. Bioactive peptides are considered beneficial in the food industries. Food-derived bioactive peptides are distinct protein fragments having beneficial pharmacological properties to human body.
Live probiotic Gram-positive bacteria belonging to cocci cell morphology are beneficial for human heath such as the decrease of cancer risk, improvement of immune and mucosal barrier system. Potential non-dairy probiotic products—a healthy approach. Food Biosci. Carbohyd Polym. Norway spruce galactoglucomannans exhibiting immunomodulating and radical-scavenging activities. Int J Biol Macromol. Hopkins HC. Kew Bull. Parkia speciosa hassk. Evidence-Based Complementary and Alternative Medicine. Suwannarat K, Nualsri C.
Genetic relationships between 4 Parkia spp. J Sci Technol. Evaluating indigenous practices for petai Parkia speciosa Hassk. Small-Scale For. Wiriadinata H, Bamroongrugsa N. Parkia speciosa. Plant Resources of South-East Asia. Some physical properties of Parkia speciosa seeds. Int Conf Food Eng Biotechnol. Lim TK. Mammea americana. Dordrecht: Springer; Nocturnal pollination of Parkia velutina by Megalopta bees in Amazonia and its possible significance in the evolution of chiropterophily.
J Trop Ecol. The pollination of Parkia by bats and its attendant evolutionary problems. Floral biology and pollination ecology of the neotropical species of Parkia. J Ecol. Parkia Leguminosae: Mimosoideae. Flora Neotropica. New york. A correlation study on the phenolic profiles and corrosion inhibition properties of mangrove tannins Rhizophora apiculata as affected by extraction solvents. Corros Sci. Zaini NA, Mustaffa F. Review: Parkia speciosa as a valuable, miracle of nature. Asian J Med Health. Antioxidant activities and polyphenolic constituents of bitter bean Parkia speciosa.
Int J Food Prop. Patterns of fruits and vegetable consumption among adults of different ethnics in Selangor, Malaysia. Int Food Res J. Drivers of sustainable waste management in Asia. Waste Manage Res. Gas chromatography Time of flight Mass spectrometry for identification of compounds from Parkia speciosa seeds extracted by supercritical.
Nat Resour Eng Technol, ;— Citrus medica: nutritional, phytochemical composition and health benefits—a review. Food Funct. Pharmacological evaluation of Parkia speciosa Hassk for antioxidant, anti-inflammatory, anti-diabetic and anti-microbial activities in vitro. Stahl W, Sies H. Antioxidant activity of carotenoids. Mol Aspects Med. Antioxidant properties of phenolic compounds.
Trends Plant Sci. Structure-activity relationship of flavonoids as antioxidant and pro-oxidant compounds. Stud Nat Prod Chem. Flavonoids as neutaceuticals: a review. Trop J Pharm Res. Premilinary studies on phytochemical screening of ulam and fruit from Malaysia. E-J Chem. Hadadare M, Salunkhe V. Simultaneous estimation of beta sitosterol and palmitic acid from methanolic extract of Caralluma Adscedens var Fimbriata by UV spetrophotometry. Balanophora spicata and lupeol acetate possess antinociceptive and anti-inflammatory activities in vivo and in vitro.
Evidence-Based Complement Altern Med. Flavour Fragr J. J Chin Chem Soc. Frve LJ. Phytosterols from the seeds of petai Parkia speciosa. University Malaysia Pahang Squalene resources and uses point to the potential of biotechnology. Lipid Technol. Dietary impact on esophageal cancer in humans: a review. Foo KY. An appraisal of the nutritional properties, therapeutic value, and novel implications of the under-utilized plant, Parkia speciosa. RSC Adv. EMBO J. Hydrogen sulfide mediates the vasoactivity of garlic. Proc Natl Acad Sci. The effects of allicin on weight in fructose-induced hyperinsulinemic, hyperlipidemic, hypertensive rats.
Am J Hypertens. Econ Bot. Randhir R, Shetty K. Developmental stimulation of total phenolics and related antioxidant activity in light-and dark-germinated corn by natural elicitors. Process Biochem. Antioxidant capacities of vegetables consumed in north east India assessed by three different in vitro assays. Int J Res Pharm Sci.
Chemometric analysis of the amino acid requirements of antioxidant food protein hydrolysates. Int J Mol Sci. Protective role of sulfhydryl reagents in oxidant lung injury. Exp Lung Res. Trypsin inhibitors from beans can certainly interfere with protein digestion, and in some species of animals do cause pancreatic enlargement and enhance chemically induced pancreatic tumors In contrast to the trypsin inhibitor, the trypsin and chymotrypsin inhibitor Bowman-Birk inhibitor found in beans, especially soybeans, has been studied as an anticancer agent As noted above, phytate is thought to contribute to the poor mineral bioavailability of beans.
Although the effect of phytate in reducing mineral bioavailability in plant foods is an important consideration, it has also been postulated that phytic acid may play a role in reducing cancer risk, possibly because of its antioxidant effects Specifically, it has been suggested that phytic acid may lower the risk of colon cancer 63 and perhaps breast cancer More than 40 y ago, diets containing beans were first shown to markedly increase flatulence In , it was reported that the oligosaccharides in beans were responsible for gas production Because of the discomfort and social embarrassment associated with flatulence, some people opt to avoid beans entirely.
Additionally, it is possible to remove substantial amounts of oligosaccharides and to markedly reduce flatulence by changing the water in which beans are boiled one or more times However, there may be some beneficial effects associated with oligosaccharide consumption. The oligosaccharides, because of their growth-promoting effect on bifidobacteria, have been hypothesized to promote the health of the colon, increase longevity, and decrease colon cancer risk 70 — In fact, for these reasons researchers in Japan have actually suggested that soybean oligosaccharides be used as a substitute for common table sugar For a more detailed discussion of oligosaccharides, see Slavin et al in this supplement Saponins are glycosides composed of a lipid-soluble aglycone that consists of either a sterol or, more commonly, a triterpenoid structure attached to water-soluble sugar residues that differ in their type and amount.
The major sources of dietary saponins are legumes, and many types of saponins can be present in the same bean. Saponins are very poorly absorbed. Although saponins were shown to lower cholesterol in some animal species, the hypocholesterolemic effects of saponins in humans are more speculative Isoflavones make up another group of phytochemicals found in beans, but for practical purposes the soybean is the only nutritionally relevant source of these compounds.
Isoflavones have received considerable attention in recent years. They are being studied for their potential role in the prevention and treatment of a number of chronic diseases including certain forms of cancer, osteoporosis, and heart disease, and also for their ability to relieve menopausal symptoms. Isoflavones are a subclass of the more ubiquitous flavonoids. The basic structural feature of flavonoid compounds is the flavone nucleus, which is composed of 2 benzene rings A and B linked through a heterocyclic pyrane C ring Figure 1.
The position of the benzenoid B ring is the basis for dividing the flavonoid class into flavonoids 2-position and isoflavonoids 3-position.
In nonfermented soyfoods, the isoflavones appear mostly as the conjugate, whereas in fermented soy products such as miso, the aglycones dominate In addition to the isoflavones found in soybeans, the intestinal microflora can convert daidzein into several different products, including the isoflavonoids equol 7-hydroxyisoflavan , dihydrodaidzein, and O -desmethylangolensin Initial interest in the beneficial effects of isoflavones focused on their estrogenic activity and their possible use in the animal feed industry as growth promoters Despite their relatively low potency, isoflavones are likely to exert physiologic effects because it has been shown that in people who consume soyfoods, serum concentrations of isoflavones are several orders of magnitude higher than those of physiologic estrogens.
The prevailing hypothesis has been that isoflavones exert antiestrogenic effects when placed in a high-estrogen environment, such as exists in premenopausal women, and estrogenic effects when in a low-estrogen environment, such as exists in postmenopausal women. In mice given DES, uterine weight decreased in those fed soy compared with control animals 1. In addition to competing with endogenous estrogens for binding to the estrogen receptor, there are several potential mechanisms by which the isoflavones may exert antiestrogenic effects reviewed in However, there are conflicting results about when isoflavones and soy exert hormonal effects and whether these effects are estrogenic or antiestrogenic in nature 95 — Particularly germane to this issue, however, are the findings of 2 human studies suggesting that soy consumption exerts estrogenic effects on breast tissue.
Epidemiologic research by Wrensch et al showed that breast-nipple-aspirate fluid is a biomarker for breast cancer risk. Women who secrete fluid are at increased risk compared with nonsecretors, and women who secrete fluid containing cells with abnormal cytology eg, hyperplastic cells are also at increased risk.
In a 9-mo study by this group, contrary to expectations, breast fluid secretion in both premenopausal and postmenopausal women taking hormone replacement therapy increased in response to soy consumption, as did the number of atypical cells in the breast fluid However, this was a pilot study that did not include a control group.
In a recent study of premenopausal women by McMichael-Phillips et al , the rate of DNA synthesis by breast cells taken from biopsies of normal breast tissue from women with benign or malignant breast disease was enhanced by 2 wk of soy feeding. Although the clinical implications of this study and the study by Petrakis et al are a matter of debate, when the in vitro, animal, and human data are considered it is difficult to conclude that soy or isoflavones are necessarily antiestrogenic in premenopausal women. Data regarding the relation between soy intake and cancer risk, including in vitro, animal, and epidemiologic results, were reviewed by Messina et al On the basis of this review, it is clear that the data are insufficient to conclude that soy consumption is protective, and yet the data certainly warrant continued investigation of this relation.
Besides isoflavones, there are a number of phytochemicals in soybeans with demonstrated anticarcinogenic activity; these include phytosterols, phytates, saponins, protease inhibitors, and a variety of phenolic acids However, most of the data point toward the isoflavones as being responsible for the hypothesized anticancer effects of soy.
Daidzein, one of the 2 primary isoflavones in soybeans, exhibits anticancer effects; eg, it inhibited the growth of HL cells implanted in the subrenal capsules of mice However, genistein has attracted most of the interest. Also, in vitro, genistein inhibits the metastatic activity of both breast and prostate cancer cells independent of the effects on cell growth. Although the antioxidant properties of genistein may contribute to the anticancer effects observed in vitro , it is more likely that these effects are due to the inhibitory actions of genistein on several enzymes involved in signal transduction, including tyrosine protein kinases , MAP kinase , and ribosomal S6 kinase Although there are in vitro, animal, and epidemiologic data supporting a protective role of soy or isoflavones against several forms of cancer, this review will consider only breast and prostate cancers because most of the focus has been on these 2 cancers.
Research on the relation between soy intake and cancer risk initially focused primarily on cancer of the breast. In large part, interest in this relation was due to the relatively low breast cancer mortality rates in Asian countries where soyfoods are commonly consumed. In Japan for example, the breast cancer mortality rate is only about one-quarter of that of the United States In addition to the low breast cancer mortality rates in Asia, 2 other early observations provided a basis for the hypothesis that soy intake decreases breast cancer risk: 1 the potential antiestrogenic effects of the soybean isoflavones as discussed above, and 2 the reduced number of 7,dimethylbenz a anthracene—induced mammary tumors observed in rats fed a diet containing soy Since this hypothesis was initially proposed, several epidemiologic studies have examined the relation between soy intake and breast cancer risk.
However, the overall intake of tofu among the subjects in this study was relatively low; the highest quartile of intake included women who consumed tofu as infrequently as 55 times per year. Also, the protective effect was primarily in Asian women born in Asia who migrated to the West and not in Asian Americans born in the United States One interpretation of these findings is that tofu intake per se is not protective but rather that it is simply reflective of some protective lifestyle common to women of Asian ancestry born in Asia but not those born in the United States.
Alternatively, the anticancer effects of tofu may be negated by a lifestyle common to women of Asian ancestry born in the United States but not those born in Asia. Not unexpectedly, only 2. Overall, the epidemiologic data are inconclusive. There is relatively little epidemiologic support for the notion that soy intake is associated with a decreased risk of postmenopausal breast cancer.
However, there are some limited data, albeit inconsistent, suggesting that soy intake is associated with a decreased risk of premenopausal breast cancer.
As noted previously, genistein has been shown to inhibit the growth of both estrogen-dependent and estrogen-independent breast cancer cells in vitro, but it is not clear that cellular concentrations of genistein in vivo would reach the in vitro concentrations required to inhibit breast cancer—cell growth. It should be noted, however, that Peterson and Barnes found that genistein inhibits the serum and epidermal growth factor—stimulated growth of normal human mammary epithelial cells with IC 50 values 11—fold lower than those for human transformed breast epithelial cells.
Thus, soy intake may help to prevent the initiation of cancer cells, rather than inhibiting the growth of existing cancer cells. In a study by Constantinou et al , neither genistein nor daidzein injected intraperitoneally inhibited N -methyl- N -nitrosourea—induced mammary tumor incidence in Sprague-Dawley rats, although both isoflavones had a moderate but not statistically significant effect on tumor multiplicity 6.
Because synergistic effects between genistein and daidzein have been noted in vitro, it would be of interest to examine their combined effects in vivo , Of course there is also the possibility that other components of soybeans, individually or in conjunction with isoflavones, are responsible for the hypothesized anticancer effects of soyfoods.
It is apparent from the human studies by Wrensch et al , McMichael-Phillips et al , and Cassidy et al , that soy or isoflavones have the potential to exert physiologic effects theoretically related to breast cancer risk. In particular, Cassidy et al found that the consumption of soy, specifically isoflavone-rich soy , extends the length of the follicular phase and decreases serum follicle-stimulating hormone and luteinizing hormone concentrations.
It is certainly not possible to conclude at this time that consumption of soyfoods in adulthood is a factor that contributes to the low breast cancer mortality rates among Japanese and Asian women, although this hypothesis still warrants rigorous investigation. Finally, there are provocative data from Brown and Lamartiniere , Lamartiniere et al , and Murrill et al suggesting that the early consumption of soyfoods by young girls may reduce breast cancer development later in life.
This research group has shown that early exposure during the neonatal or prepubertal period of life to genistein subcutaneous administration inhibits the development of dimethylbenz a anthracene-induced mammary tumors in rodents and increases the latency period — These findings offer a potential explanation for the findings of Wu et al Perhaps Asian women born in Asia are exposed to tofu at an earlier age than Asians born in the West. Certainly, the work of this group provides the basis for an intriguing line of investigation, especially because recent research indicates that early dietary exposure to genistein is also effective in retarding later development of mammary cancer.
As is the case for breast cancer, prostate cancer mortality rates vary markedly among countries. An interesting observation related to the occurrence of prostate cancer is that rates of clinical prostate cancer vary much more than rates of latent prostate cancer. This suggests that in some populations, such as the Japanese, the growth of prostate tumors is slower, the onset of prostate tumors occurs later in life, or both.
Delaying the appearance of clinical prostate tumors by even a few years could have a marked impact on mortality because prostate cancer typically occurs in older men. There is speculation that the intake of soyfoods may be a factor contributing to the low prostate cancer mortality rate in Japan, although the data in support of this hypothesis, while intriguing, are limited. Genistein inhibits the growth of both androgen-dependent and androgen-independent prostate cancer cells in vitro , Genistein also inhibits the metastatic potential of prostate cancer cells independent of cell growth inhibition, an effect that is associated with a decrease in the tyrosine phosphorylation of an unidentified molecular species In addition to the effects of genistein on signal transduction that were noted previously, there are other mechanisms by which genistein or isoflavones could reduce prostate cancer risk.
For example, even though the precise role of estrogen in prostate cancer is not well defined, the potential estrogenic effects of isoflavones may be protective because estrogens have been used successfully as a form of hormone therapy for metastatic prostate cancer This enzyme converts testosterone into the more active form of androgen, dihydrotestosterone, which stimulates the growth of prostate tissue. Until recently, there were few animal studies related to soy and prostate cancer. These findings are consistent with the epidemiologic data noted above and also with the results of a study of MNU-induced prostate tumors in Lobund-Wistar rats Rats fed a diet containing soy with a low amount of isoflavones had a shorter latency period [7.
Three studies examined the effect of soy or genistein on tumor development in rats implanted with prostate cancer cells , , Rats given genistein developed fewer tumors and fewer invasive tumors, and no genistein-treated animals developed lung metastases.
This study was the first to show that in vivo, genistein inhibits a key cellular pathway. In contrast to the favorable results discussed above, Naik et al found that although genistein inhibited prostate cancer cell growth in vitro, when Copenhagen rats were injected in the right flank with the metastatic MAT-Lylu prostate cancer line, oral doses of genistein 0. These doses more closely approximated human dietary intake than the amounts used by Schleicher et al and Dalu et al Higher doses of genistein 0.
Not surprisingly, there are limited human data available for use in evaluating the soy—prostate cancer hypothesis, although a prospective study by Severson et al found that consumption of tofu was associated with a markedly reduced risk of prostate cancer age-adjusted relative risk: 0. Of potential relevance to the effects of isoflavones on prostate cancer risk is the finding that isoflavones appear in the prostatic fluid, and that concentrations are highest in men from soyfood-consuming countries Furthermore, relative to plasma concentrations, isoflavones are concentrated several-fold in the prostatic fluid.
The red clover extract contains both genistein and daidzein as well as the methylated isoflavones, biochanin-A and formononetin, from which genistein and daidzein, respectively, are derived There has been some speculation that soy or isoflavones could be used in the treatment of existing tumors, either alone or in conjunction with conventional chemotherapeutic agents.
Development of antiangiogenesis agents is a highly promising area of cancer treatment because inhibiting the tumor-stimulated growth of new blood vessels prevents tumors from becoming larger than 1—2 mm. Tumors limited to this size are clinically insignificant The concentration of genistein required to inhibit angiogenesis in vitro, as reported initially , is certainly much higher than the genistein concentration likely to be achieved in vivo.
There is some preliminary support from in vivo research for the antiangiogenic potential of genistein. In a small study of patients with hereditary hemorrhagic telangiectasia, soy intake led to a marked reduction in nosebleeds and gastrointestinal bleeding JR Korzenik, S Barnes, unpublished observations, A larger, follow-up study is currently underway. The similarity in structure between the isoflavones and estrogen and the findings that isoflavones possess weak estrogenic properties as shown by various experimental models provided the initial basis for speculation that isoflavones may promote bone health.
Speculation about the potential benefits of isoflavones was also fueled by the similarity in chemical structure between the soybean isoflavones and the synthetic isoflavone, 7-isopropoxyisoflavone ipriflavone , which was shown to increase bone mass in postmenopausal women , Interestingly, for ipriflavone to be maximally effective it requires metabolism, and one of the metabolites of ipriflavone is the soybean isoflavone daidzein The lower rate of hip fracture among Japanese women in comparison to US women , is often cited as providing support for a protective effect of isoflavones, but this line of reasoning appears to be without merit.
The bone density of Japanese women is similar to or lower than that of US women, whose hip fracture rate is twice as high — Furthermore, the Japanese vertebral fracture rate is actually much higher than that of US women The low Japanese hip fracture rate is thought to be due at least in part to anatomical differences between white and Japanese women, such as the shorter hip axis length of Japanese women , and perhaps also to other factors such as a lower tendency to fall Until recently there were no direct data indicating that the soybean isoflavones affect bone density.
In , Anderson et al reported that genistein exhibited a biphasic effect on bone in 2 different models of ovariectomized rats, young growing rats and lactating rats, both of which were fed low-calcium diets. These studies used 3 different doses of genistein: 1. In , Arjmandi et al 98 studied the effects of soy protein on bone loss due to ovariectomy.
Sprague-Dawley rats were divided into 4 groups: 1 sham operated, 2 ovariectomized plus casein, 3 ovariectomized plus soy 0. The bone density of the right femur was highest in the group given estrogen and lowest in the ovariectomized animals fed casein. The bone density of the soy group was significantly lower than that of the estrogen and sham groups, but significantly higher than that of the ovariectomized group fed casein.
Bone density of the fourth lumbar vertebra of the soy group was equal to that of the estrogen group and significantly higher than that of both the casein and sham groups. This suggests that soy is more protective of trabecular bone than cortical bone. Similar conclusions were reached by Anderson et al In a follow-up study by Arjmandi et al , in which a similar experimental model as described above 98 was used, a soy product low in isoflavones did not affect bone density favorably but a soy product high in isoflavones did, clearly suggesting that the isoflavones are responsible for these beneficial effects of soy.
Two other rat studies suggest that genistein in particular affects bone density , In contrast to the favorable effects observed in rat studies 98 , — , Jayo et al found that in ovariectomized cynomogulus monkeys, feeding diets containing soy with or without isoflavones for 23 mo did not retard the loss of lumbar spine bone mineral content, whereas monkeys given conjugated equine estrogens had an increase in bone mineral content during this period.
Also, in rats a diet containing an amount of soy that retarded ovariectomy-induced bone loss when administered immediately after surgery had no effect when diet administration was delayed until 35 d after ovariectomy The implications of this finding may be quite significant given that recent research suggests that estrogen can exert favorable effects on bone density even when administration is delayed for many years after menopause Two human studies that examined the effects of soy consumption on bone mineral loss in postmenopausal women have been reported thus far , In both studies, soy was associated with favorable effects on bone density or content; however, the results of these studies should be considered preliminary.
Potter et al reported that after 6 mo of treatment, lumbar spine bone mineral density increased significantly compared with baseline values in postmenopausal women who consumed 40 g soy protein containing 2. Women who consumed 40 g of a mixture of casein and nonfat dry milk lost bone mineral density Not only does the magnitude of this increase raise questions about these findings, but the control subjects, who were fed wheat protein, also experienced an increase in bone mineral content which is surprising given that all the subjects were early postmenopausal women Some insight has been gained into the possible mechanism s underlying the effect of isoflavones on bone health in rats.
There are data suggesting that isoflavones may both stimulate and inhibit bone formation. For example, Fanti et al found that genistein increased osteoblast numbers and serum osteocalcin concentrations, but had no effect on osteoclast numbers. Conversely, Blair et al studied the effects of genistein on avian osteoclasts in vitro and found that osteoclast protein synthesis was significantly inhibited, an effect that might be due to the inhibitory effects of genistein on tyrosine phosphorylation.
The relation between isoflavones and bone health is provocative. Thus far, no long-term human studies have examined the effects of either soy or isoflavones on bone density or even markers of bone formation and resorption, let alone fracture risk. Consequently, although the effect of soy and isoflavones on bone health constitutes an exciting area of research, no firm conclusions can be reached at this time. Fortunately, because of the number of studies underway, it is likely that a much better understanding of this issue will be obtained within a relatively short period of time.
Legumes have traditionally been an important part of the diets of many cultures throughout the world. In contrast, in developed countries beans currently have only a minor dietary role. The nutritional profile of beans shows that they have much to offer; beans are high in protein, low in saturated fat, and high in complex carbohydrates and fiber. Beans are also a good source of several micronutrients and phytochemicals.
It has been hypothesized that isoflavones reduce the risk of cancer, heart disease, and osteoporosis, and also help relieve menopausal symptoms.
Although there is much to learn about the effects of isoflavones on chronic disease risk, this area of research holds considerable potential. Given the nutrient profile and phytochemical contribution of legumes, nutritionists should make a concerted effort to encourage the public to consume more beans in general and more soyfoods in particular.
Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide. Sign In or Create an Account. Sign In. Advanced Search. Article Navigation. Close mobile search navigation Article Navigation. Volume Article Contents. Legumes and soybeans: overview of their nutritional profiles and health effects Mark J Messina. Oxford Academic. Google Scholar.
Cite Citation. Permissions Icon Permissions. Legumes , soybeans , beans , phytochemicals , isoflavones , genistein , soyfoods , breast cancer , prostate cancer , cancer prevention , osteoporosis prevention , dietary fiber. TABLE 1. Open in new tab. Open in new tab Download slide. Google Preview. US Department of Agriculture. Dietary intakes of adolescent females consuming vegetarian, semi-vegetarian, and omnivorous diets. Search ADS. UK mean daily intakes of saponins—intestine-permeabilizing factors in legumes. Nut consumption, vegetarian diets, ischemic heart disease risk, and all-cause mortality: evidence from epidemiologic studies.
Nuts and their bioactive constituents: effects on serum lipids and other factors that affect disease risk. Cereals, legumes, and chronic disease risk: evidence from epidemiologic studies. Consumer and Food Economic Institute. National Research Council. Relationship between amino acid scores and protein quality indices based on rat growth. Corrected relative net protein ratio CRNPR method based on differences in rat and human requirements for sulfur amino acids.
Evaluation of protein digestibility-corrected amino acid score method for assessing protein quality of foods. The protein digestibility-corrected amino acid score method overestimates quality of proteins containing antinutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. Estimation of the renal net acid excretion by adults consuming diets containing variable amounts of protein.