Search

The compound S -equol (4′,7-dihydroxy-isoflavandiol), a gut bacterial metabolite of isoflavone daidzein, benefits health, but only 20–60% of humans can produce equol after ingesting isoflavones, and it exists only in foods of animal origin in trace amounts. A recent study found a source of stinky tofu contained S -equol. As stinky tofu is a popular traditional fermented soy food in Taiwan, we analyzed S -equol contents of commercial samples, surveyed the intake frequency, and investigated the bioavailability of S -equol by monitoring urinary kinetics following ingestion. Our results showed 91% of the 138 stinky tofu dishes contained S -equol. The mean content per serving (average 198 g) was 2.3 ± 2.5 mg, the highest being 16.3 mg. Stinky tofu eaters on average ingested this food 3.3 times per month. S -equol from ingested stinky tofu appeared in urine within 1 h, reaching maximum excretion at 3.4 h, and 67% of the ingested S -equol was recovered in urine, indicating a rapid and high absorption. Our studies suggest stinky tofu can be a promising dietary source of S -equol for its high content and bioavailability. Further study on the S -equol producing bacteria in stinky tofu is merited for the development of other S -equol rich soy products.

In this study, we aimed to evaluate the inhibitory effect of wild bitter melons (WBM; Momordica charantia Linn. var. abbreviata Ser.) on Propionibacterium acnes-induced inflammation and to identify the bioactive components. Our results showed that ethyl acetate (EA) extract of WBM fruit in vitro potently suppressed pro-inflammatory cytokine and matrix metalloproteinase (MMP)-9 levels in P. acnes-stimulated THP-1 cells. Furthermore, concomitant intradermal injection of WBM EA extract in mice effectively attenuated P. acnes-induced ear swelling and granulomatous inflammation. To further investigate the bioactive components, we found that both saponifiable (S) and nonsaponifiable (NS) fractions of WBM EA extract significantly suppressed pro-inflammatory cytokine and MMP-9 levels. Phytol and lutein, identified in the NS fraction, also inhibited cytokine production. Moreover, S and NS fractions of EA extract, phytol and lutein, activated peroxisome proliferator-activated receptor (PPAR) α and β in the transactivation assay. Our results suggested that PPARα or PPARγ signalling may contribute, at least in part, to the anti-inflammatory activity of WBM.

Propionibacterium acnes play an important role in the pathogenesis of acne by inducing certain inflammatory mediators and comedogenesis. The objective of this study was to evaluate the antimicrobial and anti-inflammatory effects of herbal extracts against P. acnes. Among the ten tested herbs, methanolic extracts of rose (Rosa damascene), duzhong (Eucommia ulmoides Oliv.), and yerba mate (Ilex paraguariensis) were found to inhibit the growth of P. acnes with respective minimum inhibitory concentrations of 2, 0.5, and 1 mg/ml. In addition, duzhong and yerba mate extracts reduced the secretion of pro-inflammatory cytokines such as tumour necrosis factor-α, interleukin (IL)-8, and IL-1β by human monocytic THP-1 cells pretreated with heat-killed P. acnes at a concentration of 0.1 mg/ml. Our results suggested that duzhong and yerba mate extracts possess both antimicrobial and anti-inflammatory effects against P. acnes and can possibly be used as therapeutic agents for acne.

This study was aimed to identify compounds in bitter gourd (Momordica charantia) ethyl acetate extract (EAE), which inhibit lipopolysaccharide-induced prostaglandin E2 (PGE2) production in RAW264.7 cells. Bitter gourd EAE was partitioned between n-hexane and methanol/H2O (90/10). The hexane fraction was further separated by repeated silica gel chromatographies, and a reverse phase (RP) C18 chromatography. Fraction RP-10 showed the highest inhibition effect on PGE2 production (Max inhibition = 96%, IC50 = 2.3 μg/ml) and was identified to be triglycerides constituted of short and medium chain fatty acids by 1H NMR, IR and H–HCOSY, and dicarboxylic acids by GC/MS. Fatty acids with 3–20 carbons were tested for the inhibitory activity, and capric acid exhibited the highest effect (Max inhibition = 99%, IC50 = 6.5 μM). In conclusion, triglycerides composed of short and medium chain fatty acids and dicarboxylic acids in bitter gourd inhibit PGE2 production, and capric acid is the most potent inhibitor among the fatty acids.

Sesame lignans have multiple functions and were recently reported to have potential as sources of phytoestrogens. Sesame oils used in Taiwan are expelled from roasted sesame seeds with dark colour and strong flavour. This study analyzed lignan contents of 14 brands of sesame oils, and found their mean of total lignans to be 11.5 mg/g; 82% and 15% of the lignans were sesamin, and sesamolin, respectively. Sesamol contents were relatively higher in those with darker colour. In use as a cooking oil, heating at 180 °C for 4 min did not change the content of lignans, but the level of sesamol increased after heating at 180 °C for 20 min. Heating at 200 °C for 20 min caused a significant loss of sesamolin and sesamol. From our calculation, ingestion of 10 g of sesame oil is adequate to provide the level of lignans that might benefit cardiovascular health, as found by other studies. Cooking at temperatures above 200 °C will cause loss of some lignans, but sesamin, a source of phytoestrogen, is relatively heat-stable.

Sesame ingestion has been shown to improve blood lipids in humans and antioxidative ability in animals. Sesamin, a sesame lignan, was recently reported to be converted by intestinal microflora to enterolactone, a compound with estrogenic activity and also an enterometabolite of flaxseed lignans, which are known to be phytoestrogens. Whether sesame can be a source of phytoestrogens is unknown. This study was designed to investigate the effect of sesame ingestion on blood sex hormones, lipids, tocopherol, and ex vivo LDL oxidation in postmenopausal women. Twenty-six healthy subjects attended, and 24 completed, this randomized, placebo-controlled, crossover study. Half of them consumed 50 g sesame seed powder daily for 5 wk, followed by a 3-wk washout period, then a 5-wk 50-g rice powder placebo period. The other half received the 2 supplements in reverse order. After sesame treatment, plasma total cholesterol (TC), LDL-C, the ratio of LDL-C to HDL-C, thiobarbituric acid reactive substances in oxidized LDL, and serum dehydroepiandrosterone sulfate decreased significantly by 5, 10, 6, 23, and 18%, respectively. The ratio of alpha- and gamma-tocopherol to TC increased significantly by 18 and 73%, respectively. All of these variables differed significantly between the 2 treatments. Serum sex hormone-binding globulin and urinary 2-hydroxyestrone (n = 8) increased significantly by 15 and 72%, respectively, after sesame treatment, and these concentrations tended to differ (P = 0.065 and P = 0.090, respectively) from those after the placebo treatment. These results suggest that sesame ingestion benefits postmenopausal women by improving blood lipids, antioxidant status, and possibly sex hormone status.

The effect of dietary iron overload on lipid peroxidation (LP), prostaglandin (PG) synthesis and lymphocyte proliferation was examined in young and old F344 rats. Rats 4 and 19-22 mo old were fed AIN-76 diet for 11-12 wk supplemented with 2.5% carbonyl iron obtained from two sources (Type A and B). Animals supplemented with Type A iron showed reduced food intake and weight gain associated with marked increases in extrahepatic and hepatic iron concentration. Rats receiving Type B iron had food intakes and body weights similar to those of controls but exhibited small increases in tissue iron concentration. Old control rats compared to young had significantly higher conjugated dienes (CD) in hepatic microsomes. Feeding Type A iron diets induced a significantly higher level of CD in hepatic microsomes from old rats compared to young rats. Iron overloaded rats also showed highly correlated (r = 0.94) increases in the urinary excretion of thiobarbituric acid-reactive substances and PG metabolites indicating increased in vivo LP and PG synthesis. Mitogen-stimulated PGE2 synthesis in young rats was increased at 4 wk in association with enhanced T-cell proliferation stimulated by Concanavalin A. Lymphocyte proliferation was significantly lower in old than in young control or iron-treated rats. The lack of efficacy of Type B vs. Type A iron appears due to a larger particle size and lower bioavailability. In conclusion, iron overloading increases in vivo LP and PG metabolism. Furthermore, the mitogenic response to Concanavalin A in young rats is enhanced after 4 wk of iron overloading.