Extracted Anaxagorea luzonensis A. Gray Restored Impairment of Endothelium-Dependent Vasorelaxation Induced by Homocysteine Thiolactone in Rat Aortic Rings.

OBJECTIVE: To investigate the beneficial effects of Anaxagorea luzonensis (AL) extract on homocysteine thiolactone (HTL)-induced impairment of endothelium-dependent relaxation in rat aortic rings. The mechanisms involved in the effects of AL on endothelial dysfunctions by HTL are also examined. MATERIAL AND METHOD: Aortic rings from male Wistar rats were co-incubated for 90 minutes with L-arginine (3 mM), a precursor of nitric oxide (NO); superoxide dismutase (SOD, 200 U/mL), a scavenger of superoxide anion; indomethacin (10 µM), a cyclooxygenase (COX) inhibitor; SC560 (10 µM), a COX-1 inhibitor; NS398 (10 µM), a COX-2 inhibitor; or SQ29548 (1 µM), a thromboxane A2 receptor antagonist in the presence of HTL (1 mM). After 90 minutes of incubation period, the rings were pre-contracted with methoxamine, and then carbachol was cumulatively added to the bath. AL (1 and 3 µg/mL) was co-incubated with 1 mM HTL in the presence of N(G)-nitro-L-arginine methyl ester (L-NAME, 300 µM), a NO synthase inhibitor and p-hydroxymercurybenzoate (PHMB, 10 µM), a sulfhydryl group blocking agent. Changes in tension were measured using an isometric force transducer and recorded on the PowerLab. RESULTS: Endothelium-dependent vasorelaxation to carbachol was impaired after exposure of aortic rings to HTL (0.3 and 1 mM). The inhibitory effects of HTL (1 mM) on relaxant responses to carbachol were restored by L-arginine, SOD, indomethacin, SC560 and SQ29548, but not NS398. Interestingly, AL reduced impairment of vasorelaxation induced by HTL (1 mM). However, L-NAME and PHMB largely inhibited the protective effects of AL. CONCLUSION: These results suggest that HTL-induced impairment of endothelium-dependent vasorelaxation may occur via decreased NO release, and generation of oxygen free radical. This study first shows that enhancement of TxA2 production via COX-1 pathway is involved in HTL-induced endothelial dysfunctions. The protective effects of AL on impairment of relaxation by HTL may be related to increasing NO production and sulfhydryl-dependent.

Effect of Short-Term Oral Administration of Phikud Navakot in Rats.

BACKGROUND: Phikud Navakot (PN), composed of nine herbs and used as a main component of Yahom Navakot, is used in traditional Thai medicine against dizziness and fainting. OBJECTIVE: To investigate the effects of PN on blood pressure, heart rate (HR), and antioxidant properties on male Sprague Dawley rats. MATERIAL AND METHOD: All rats were weighted everyday in the morning, after that, PN (10, 50, 100, 200 and 400 mg/kg BW) were given oroesophageal feeding for seven days. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and HR were measured once per two days. At the end of the experiment, the blood was taken for determination of biochemical and hematological parameters, and lipid peroxidation in serum. The heart was immediately removed for Western blot analysis. RESULTS: SBP DBP and MAP of rats were transiently increased after 1 day of PN (100 mg/kg BW) treatment. Meanwhile, HR did not change throughout the experiment. PN (400 mg/kg BW) significantly increased (p< 0.05) the percentage of neutrophils in blood after 7 days of administration. PN treatment has no effect on biochemical parameters and peroxidation of lipid. In addition, ingestion of PN (100 mg/kg BW) significant increased (p < 0.05) HO-1 expression, but did not change ERK1/2 and Bax/Bcl-2 ratio when compared with the control group. CONCLUSION: The results may possibly support the use of PN for prevention and/or alleviation of cardiovascular disorders, caused by reactive oxygen species. However, long-term treatment of PN has to be further studies.

Effect of daily treatment with Thai herb, Kaempferia parviflora, in Hershberger assay using castrated immature rats.

The aim of the present study was to investigate the testosterone-like effect of Kaempferia parviflora (KP). Castrated immature rats were randomized and divided into two groups (control and KP-treatment groups). The rats (n=7-8) were treated daily for 5 days by oral route with water in the control group and 1,000 mg/kg of KP in the treatment group. All rats were decapitated 24 h after their last dose and then blood samples were collected for assay of serum FSH, LH, testosterone, progesterone and corticosterone levels. The seminal vesicles plus coagulating glands, ventral prostate, levator ani muscle plus bulbocavernosus muscle, glans penis, kidneys and the adrenal glands were collected and weighed for organ wet weight. Body weight and weight of food intake were recorded throughout the study period. The results show that relative body weight gain in the KP-treatment group was significantly increased 24 and 48 h after the first dose (P<0.05) and then was indistinguishable from the control group. There were no significant differences in the relative reproductive and non-reproductive organ weights between the groups, although all organ weights, except for the glans penis, tended to increase in the KP-treatment group. The serum testosterone levels were significantly increased in the KP-treatment group. There were no significant differences in the serum FSH, LH, progesterone, or corticosterone levels between the groups, even though the serum progesterone level tended to increase and serum LH level tended to decrease in the KP-treatment group. The present study indicates that KP has no testosterone-like effect on reproduction in male rats.