Ching-jang Huang

Bitter gourd (Momordica charantia) extract activates peroxisome proliferator-activated receptors and upregulates the expression of the acyl CoA oxidase gene in H4IIEC3 hepatoma cells.

Peroxisome proliferator-activated receptor α (PPARα) is a ligand-dependent transcription factor that regulates the expression of genes involved in lipid metabolism and transport. Ligands/activators of PPARα, like fibrate-type drugs, may have hypolipidemic effects. To identify food that contains activators of PPARα, a transactivation assay employing a clone of CHO-K1 cells stably transfected with a (UAS)4-tk-alkaline phosphatase reporter and a chimeric receptor of Gal4-rPPARα LBD was used to screen ethyl acetate (EA) extracts of a large variety of food materials. It was found that the EA extract of bitter gourd (Momordica charantia), a common oriental vegetable, activated PPARα to an extent that was equivalent to or even higher than 10 µM Wy-14643, a known ligand of PPARα. This extract also activated PPARγ to a significant extent which was comparable to 0.5 µM BRL-49653. The activity toward PPARα was mainly in the soluble fraction of the organic solvent. The EA extract prepared from the whole fruit showed significantly higher activity than that from seeds or flesh alone. The bitter gourd EA extract was then incorporated into the medium for treatment of a peroxisome proliferator-responsive murine hepatoma cell line, H4IIEC3, for 72 h. Treated cells showed significantly higher activity of acyl CoA oxidase and higher expressions of mRNA of this enzyme and fatty acid-binding protein, indicating that the bitter gourd EA extract was able to act on a natural PPARα signaling pathway in this cell line. It is thus worth further investigating the PPAR-associated health benefits of bitter gourd.

Bitter melon (Momordica charantia L.) inhibits adipocyte hypertrophy and down regulates lipogenic gene expression in adipose tissue of diet-induced obese rats.

Bitter melon (Momordica charantia; BM) has been shown to ameliorate diet-induced obesity and insulin resistance. To examine the effect of BM supplementation on cell size and lipid metabolism in adipose tissues, three groups of rats were respectively fed a high-fat diet supplemented without (HF group) or with 5 % lyophilised BM powder (HFB group), or with 0.01 % thiazolidinedione (TZD) (HFT group). A group of rats fed a low-fat diet was also included as a normal control. Hyperinsulinaemia and glucose intolerance were observed in the HF group but not in HFT and HFB groups. Although the number of large adipocytes (>180 microm) of both the HFB and HFT groups was significantly lower than that of the HF group, the adipose tissue mass, TAG content and glycerol-3-phosphate dehydrogenase activity of the HFB group were significantly lower than those of the HFT group, implying that BM might reduce lipogenesis in adipose tissue. Experiment 2 was then conducted to examine the expression of lipogenic genes in adipose tissues of rats fed low-fat, HF or HFB diets. The HFB group showed significantly lower mRNA levels of fatty acid synthase, acetyl-CoA carboxylase-1, lipoprotein lipase and adipocyte fatty acid-binding protein than the HF group (P < 0.05). These results indicate BM can reduce insulin resistance as effective as the anti-diabetic drug TZD. Furthermore, BM can suppress the visceral fat accumulation and inhibit adipocyte hypertrophy, which may be associated with markedly down regulated expressions of lipogenic genes in the adipose.

Methanol Extract of Antrodia camphorata Protects against Lipopolysaccharide-Induced Acute Lung Injury by Suppressing NF- κB and MAPK Pathways in Mice

Antrodia camphorata (AC) has been used as a herbal medicine for drug intoxication for the treatment of inflammation syndromes and liver-related diseases in Taiwan. This study demonstrates the protective effect of the methanol extract of AC (MAC) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Mice were treated with MAC 1 h before the intratracheal (I.T.) instillation of LPS challenge model. Lung injury was evaluated 6 h after LPS induction. Pretreatment with MAC markedly improved LPS-induced histological alterations and edema in lung tissues. Moreover, MAC also inhibited the release of pro-inflammatory mediators such as nitric oxide (NO), tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), and IL-6 at 6 h in the bronchoalveolar lavage fluid (BALF) during LPS-induced lung injury. Furthermore, MAC reduced total cell number and protein concentrations in the BALF the pulmonary wet/dry weight (W/D) ratio, and myeloperoxidase activity and enhanced superoxide dismutase (SOD) activity in lung tissues. MAC also efficiently blocked protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and phosphorylation of mitogen-activated protein kinases (MAPKs) and inhibited the degradation of nuclear factor-kappa B (NF-κB) and IκBα. This is the first investigation in which MAC inhibited acute lung edema effectively, which may provide a potential target for treating ALI. MAC may utilize the NF-κB and MAPKs pathways and the regulation of SOD activity to attenuate LPS-induced nonspecific pulmonary inflammation.

Isolation and Identification of Cucurbitane-Type Triterpenoids with Partial Agonist/Antagonist Potential for Estrogen Receptors from Momordica charantia

This study aims at investigating the estrogenic activity and active cucurbitane-type triterpenoid compounds of bitter gourd (Momordica charantia, MC) using a transactivation assay for estrogen receptors (ER) α and β. The lyophilized fruits of MC were exhaustively extracted with ethyl acetate (EA) and 95% ethanol (EtOH), sequentially. The nonsaponifiable fraction (NS) of the EA extract as well as the acid hydrolyzed EtOH extract (AH) was fractionated and isolated by repeated column chromatography and further purified by preparative HPLC or RP-HPLC. One known compound, 5β,19-epoxycucurbita-6,24-diene-3β,23ξ-diol (6), was isolated from the NS, and five new compounds (1-5) were isolated from AH and identified as cucurbita-6,22(E),24-trien-3β-ol-19,5β-olide (1), 5β,19-epoxycucurbita-6,22(E),24-triene-3β,19-diol (2), 3β-hydroxycucurbita-5(10),6,22(E),24-tetraen-19-al (3), 19-dimethoxycucurbita-5(10),6,22(E),24-tetraen-3β-ol (4), and 19-nor-cucurbita-5(10),6,8,22(E),24-pentaen-3β-ol (5). In the noncytotoxic concentration range, compounds 1, 2, 5 and 6 showed weak agonistic activity via ER α and β. Compounds 1, 2, 3 and 6 significantly antagonized the transactvation of 17β-estradiol (E(2)) via both ER α and β. In conclusion, this study demonstrates, for the first time as far as we know, the partial agonist/antagonist activity via ER of four new and one known cucurbitane-type triterpenoids from MC. Further studies are worthy to explore the selective estrogen receptor modulator (SERM) activity of MC.

Wild bitter melon (Momordica charantia Linn. var. abbreviata Ser.) extract and its bioactive components suppress Propionibacterium acnes-induced inflammation.

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.

The up-regulation of hepatic acyl-CoA oxidase and cytochrome P450 4A1 mRNA expression by dietary oxidized frying oil is comparable between male and female rats.

We previously demonstrated that oxidized frying oil (OFO) activates peroxisome proliferator-activated receptor α (PPARα) and up-regulates hepatic acyl-CoA oxidase (ACO) and cytochrome P450 4A1 (CYP4A1) genes in male rats. As female rats were shown to be less responsive to some peroxisome proliferators (PP), this study compared the expression of a few PPARα target genes in male and female rats fed diets containing OFO. Male and female rats were fed a diet containing 20 g/100 g OFO (O diet) or fresh soybean oil (F diet) for 6 wk. Both male and female rats fed the O diet showed significantly higher liver weight, hepatic ACO and catalase activities, CYP4A protein, and expression of ACO and CYP4A1 mRNA (P<0.05) compared with their control groups. The mRNA expression of two other PPARα target genes, FA-binding protein and HMG-CoA synthase, were marginally increased by dietary OFO (P=0.0669 and 0,0521, respectively). Female rats fed the O diet had significantly lower CYP4A protein than male rats fed the same diet. The remaining OFO-induced effects were not significantly different between male and female rats fed the O diet. These results indicate that dietary OFO, unlike clofibrate or other PP, had minimal sexual dimorphic effect on the induction of hepatic PPARα target gene expression.

Wild bitter gourd improves metabolic syndrome: A preliminary dietary supplementation trial

BackgroundBitter gourd (Momordica charantia L.) is a common tropical vegetable that has been used in traditional or folk medicine to treat diabetes. Wild bitter gourd (WBG) ameliorated metabolic syndrome (MetS) in animal models. We aimed to preliminarily evaluate the effect of WBG supplementation on MetS in Taiwanese adults.MethodsA preliminary open-label uncontrolled supplementation trial was conducted in eligible fulfilled the diagnosis of MetS from May 2008 to April 2009. A total of 42 eligible (21 men and 21 women) with a mean age of 45.7 ± 11.4 years (23 to 63 years) were supplemented with 4.8 gram lyophilized WBG powder in capsules daily for three months and were checked for MetS at enrollment and follow-up monthly. After supplementation was ceased, the participants were continually checked for MetS monthly over an additional three-month period. MetS incidence rate were analyzed using repeated-measures generalized linear mixed models according to the intention-to-treat principle.ResultsAfter adjusting for sex and age, the MetS incidence rate (standard error, p value) decreased by 7.1% (3.7%, 0.920), 9.5% (4.3%, 0.451), 19.0% (5.7%, 0.021), 16.7% (5.4%, 0.047), 11.9% (4.7%, 0.229) and 11.9% (4.7%, 0.229) at visit 2, 3, 4, 5, 6, and 7 compared to that at baseline (visit 1), respectively. The decrease in incidence rate was highest at the end of the three-month supplementation period and it was significantly different from that at baseline (p = 0.021). The difference remained significant at end of the 4th month (one month after the cessation of supplementation) (p = 0.047) but the effect diminished at the 5th and 6th months after baseline. The waist circumference also significantly decreased after the supplementation (p < 0.05). The WBG supplementation was generally well-tolerated.ConclusionThis is the first report to show that WBG improved MetS in human which provides a firm base for further randomized controlled trials to evaluate the efficacy of WBG supplementation.

A high oxidised frying oil content diet is less adipogenic, but induces glucose intolerance in rodents

Oxidised frying oil (OFO) and fish oil have been shown to be peroxisome proliferator-activated receptor (PPAR)alpha activators and their ingestion results in pleotropic peroxisome proliferator responses in rats. To examine the effect of dietary OFO on adiposity, four groups of weanling Sprague-Dawley rats were fed isoenergetically with, respectively, a low fat basal diet containing 5 g/100 g of fresh soybean oil (LSB) or a high fat diet containing 20 g/100 g of fresh soybean oil (HSB), OFO (HO) or fish oil (HF). The tissue mass, cell size and lipid/DNA ratio in the retroperitoneal fat pad and serum leptin levels were lowest in the HO group (P < 0.05), indicating that dietary OFO has a greater anti-adipogenic action than dietary fish oil. However, a tendency to hyperglycaemia was observed in the HO group (P = 0.0528). To examine the effect of dietary OFO on glucose tolerance, three groups of rats and three groups of mice were fed, respectively, the LSB, HSB or HO diet, and an oral glucose tolerance test was performed. After oral glucose load, the area under the curve for blood glucose (AUCglu) over 2 h was significantly higher, and that for serum insulin (AUCins) over 90 min was significantly lower, in the HO group than in the other two groups (P < 0.05). These results demonstrate that, in rats and mice, a high OFO diet is less adipogenic, but induces glucose intolerance.

Two unhealthy dietary habits featuring a high fat content and a sucrose-containing beverage intake, alone or in combination, on inducing metabolic syndrome in Wistar rats and C57BL/6J mice.

To establish animal models with diet-induced metabolic disorders similar to human metabolic syndrome, 2 unhealthy dietary habits featuring a high fat content and a sucrose-containing beverage intake, alone or in combination, were tested on Wistar rats and C57BL/6J mice. The 2 dietary habits were, respectively, simulated by feeding a high-fat diet (regimen A) or additionally providing 30% sucrose (wt/vol) in the drinking water (regimen B). Using a 2 x 2 factorial design, 4 groups of animals were fed chow diet plus plain water (group C), high-fat diet (30% [wt/wt] fat) plus plain water (group A), chow diet plus sucrose in drinking water (group B), and high-fat diet plus sucrose in drinking water (group AB) for 26 weeks. In Wistar rats, regimen B caused a significant increase in visceral fat; serum levels of lipids, glucose, insulin, and uric acid; insulin resistance; and blood pressure, whereas regimen A only caused a significant increase in visceral fat and serum insulin levels (P < .05). In contrast, regimen A induced a full array of metabolic syndrome in C57BL/6J mice; but regimen B only caused slight obesity and hyperlipidemia. In both Wistar rats and C57BL/6J mice, there were no additive effects of the 2 regimens, indicated by significant interactions between regimens A and B on the metabolic indexes measured. These results show that, in terms of inducing metabolic syndrome, Wistar rats are more responsive to sucrose water regimen, whereas C57BL/6J mice are more responsive to the high-fat diet regimen.

Phytoestrogenic Compounds in Alfalfa Sprout (Medicago sativa) beyond Coumestrol

Coumestrol has long been known as the phytoestrogenic compound in alfalfa. However, it has been demonstrated that the ethyl acetate extract of alfalfa sprout (AEA) attenuated the disease severity and increased survival and life span of autoimmune-prone MRL-lpr/lpr mice. Coumestrol, on the contrary, decreased the survival. This study thus aimed to isolate and identify phytoestrogenic compounds other than coumestrol in AEA. AEA was fractionated and separated by successive silica gel chromatography and preparative HPLC. The activity of collected fractions was tracked by a transactivation assay for ERα and ERβ, respectively. In addition to coumestrol, liquiritigenin, isoliquiritigenin, loliolide, and (4S,6S)- and (4R,6S)-4-hydroxy-6-pentadecyltetrahydropyr-2-one were isolated and chemically identified. Except for loliolide, these compounds showed higher transactivation via ERβ than via ERα. The maximal activation via ERα of coumestrol reached 80% that of 1 nM 17β-estradiol (E(2)), whereas the activations of the remaining five compounds as well as AEA ranged from 8 to 49%. In addition, isoliquiritigenin, loliolide, and (4S,6S)- and (4R,6S)-4-hydroxy-6-pentadecyltetrahydropyr-2-one, but not coumestrol, preferentially inhibited 1 nM E(2) induced ERα activation, compared to that ERβ activation. The selectivity of these phytoestrogens might account for the difference between the effects of AEA and coumestrol in autoimmune-prone MRL-lpr/lpr mice observed previously.