Introduction: Triphala, consisting of three fruits, Phyllanthus emblica L. (Phyllanthaceae), Terminalia bellirica (Gaertn.) Roxb. (Combretaceae), and T. chebula Retz, is a well-recognized Ayurvedic herbal formulation, used for various therapeutic purposes, including the treatment of dyslipidemia. Inhibitory activity against 3‑hydroxy‑3‑methylglutaryl‑coenzyme A (HMG‑CoA) reductase, a rate-limiting enzyme in the endogenous cholesterol synthesis pathway, is an essential target for the management of hypercholesterolemia. This in silico study aimed to investigate the HMG-CoA reductase inhibitory activity of the phytochemical compounds derived from Triphala formulation by employing molecular docking analysis. Methods: Ten phytochemical constituents of Triphala formulation were selectively used for docking study by using the HMG-CoA reductase template (PDB: 1HWK). Docking analysis was performed using AutoDock 4.2. The candidates were ranked by the binding energy parameters. Results: From the docking studies, the phytochemical compounds with HMG-CoA reductase inhibition could be classified into 4 groups, including phytosterols, polyphenols, tannins, and flavonoids. Beta-sitosterol exhibited the highest binding affinity to HMG-CoA reductase with a binding energy of -7.75 kcal/mol. Conclusion: These 10 phytochemical compounds in Triphala potentially exert their cholesterol-lowering effects via inhibition against HMG-CoA reductase. Nonetheless, further in vitro and in vivo experiments should be conducted subsequently to confirm this finding.

Introduction: Xanthine oxidase inhibitors with strong antioxidant activity are promising candidates for the treatment of gout and reactive oxygen species (ROS)-related disorders. 3,4,5-Trihydroxycinnamic acid (THCA), a natural hydroxycinnamic acid, exhibits strong antioxidant activities. This study investigated its xanthine oxidase inhibitory and antioxidant activities in comparison with sinapic acid, caffeic acid, and allopurinol. Methods: In vitro xanthine oxidase inhibitory assay and a Lineweaver-Burk plot were used to measure enzyme inhibition activity and pattern. A docking study was used to explore hydroxycinnamic acid-xanthine oxidase interactions. Antioxidant activity was determined by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Results: THCA (IC50 = 61.60±8.00 µM) inhibited xanthine oxidase more potently than sinapic acid and caffeic acid (IC50s = 117.00±4.00 and 214.00±5.00 µM), but less than allopurinol (IC50 = 2.84±0.41 µM) (P<0.05). THCA and allopurinol were competitive xanthine oxidase inhibitors with inhibition constants (Ki ) of 170 and 2.12 µM, respectively. The docking investigation revealed that hydroxycinnamic acids occupied the enzyme active site near the molybdopterin core. THCA formed one more hydrogen bond with the enzyme active site than the other hydroxycinnamic acids, which could account for its higher inhibitory potency. THCA had significantly the strongest DPPH-radical scavenging activity (IC50 = 16.45±3.35 μM) and higher than ascorbic acid (IC50 = 33.16±7.38 μM) (P<0.05). Conclusion: THCA inhibits xanthine oxidase and has good antioxidant properties even more than sinapic acid and caffeic acid. Thus, it is a promising natural active compound that should be further investigated for the treatment of gout and other ROS-related disorders.

Croton tiglium L. seeds, a component of many recipes of Thai traditional medicine (TTM), had to undergo the Thai traditional detoxification process (TDP) before being used. However, this detoxification process has never been scientifically proven for its effectiveness. Thus, this research aimed to investigate the effects of TDP on purgative effect and acute toxicity, as well as the identification of some chemical constituents in C. tiglium seeds before (CB) and after (CA) treatment. The purgative effect and acute toxicity of CB and CA powders were evaluated using Wistar rats. The amounts of phorbol-12-myristate-13-acetate (PMA) and crotonic acid in the CB and CA powders were determined using HPLC. The results showed no acute toxicity in the rats administered CB and CA powders at doses of 300–2000 mg/kg of body weight (BW). However, CB and CA caused a dose-dependent increase in the number of fecal pellets as well as an increase in the amount of wet and dry feces. Interestingly, only CB, at the dose of 100 mg/kg, caused a significant purgative effect. The TDP was also found to affect the amounts of PMA and crotonic acid. While the amount of PMA in C. tiglium seed powder decreased from 1.59 mg/g in CB to 1.26 mg/g in CA, the amount of crotonic acid decreased from 0.001 mg/g in CB to an undetectable level in CA. This investigation demonstrated that TDP not only reduced the purgative effect and toxicity of croton seeds but also the amounts of PMA and crotonic acid.

Introduction: Methicillin-resistant Staphylococcus aureus (MRSA)-derived biofilm formation is a crucial virulence factor, which essentially contributes to therapeutic challenges. This study aims to evaluate the antibiofilm and antibacterial formation activities of lupinifolin, a prenylated flavanone derived from Derris reticulata Craib. stem, in combination with protein synthesis inhibitors. Methods: The crystal violet biofilm formation assay was performed to determine the biofilm formation activity. The synergistic antibacterial activities were evaluated using the checkerboard and time-kill assays. Results: Lupinifolin and tetracycline significantly reduced MRSA biofilm formation with IC50 values of 15.32 ± 5.98 and 13.42 ± 5.90 µg/mL, respectively. On the contrary, the individual treatment of streptomycin and clindamycin tended to enhance biofilm formation. Lupinifolin at the sub-MIC of 8 µg/mL in combination with certain sub-MICs of tetracycline (8 and 16 µg/mL), streptomycin (16, 32, and 64 µg/mL), or clindamycin (4, 8, and 16 µg/mL) caused significant inhibitions against MRSA biofilm formation (P<0.05). The combination of lupinifolin and streptomycin exhibited a synergy (FIC index <0.625), confirmed in the time-kill assay. Conversely, the combination of lupinifolin and tetracycline or clindamycin resulted in no interaction (FIC indices of 1.0078 and <1.0156, respectively). Conclusion: The antibacterial synergy of lupinifolin and streptomycin possibly contributed to their antibiofilm-forming activity. However, the combinations of lupinifolin and tetracycline or clindamycin conceivably executed their antibiofilm activity directly against the MRSA biofilm formation process. These findings indicate a potential role for lupinifolin as an antibiofilm enhancer to diminish MRSA biofilm formation.

Context: The leaves of Lagerstroemia speciosa (L.) Pers. (banaba) have been consumed traditionally in several Southeast Asian countries for the treatment of diabetes mellitus. The plasma glucose lowering actions of this medicinal plant were proposed to be linked with several mechanisms of action. However, its inhibitory actions against α-amylase and α-glucosidase, which play a major role in the regulation of postprandial plasma glucose, have not been clearly established. Aims: This study thus aimed to investigate the effects of Lagerstroemia speciosa (L.) Pers. aqueous and ethanolic leaf extracts (LSA and LSE extracts, respectively) on in vitro carbohydrate-digesting enzyme activities and enzyme kinetics. Settings and Design: In vitro carbohydrate-digesting enzyme activity assay. Materials and Methods: The activities of α-amylase and α-glucosidase were indicated by the amounts of maltose and p-nitrophenol generated in the reactions, respectively. Statistical analysis used: The data were analysed by using one-way ANOVA, followed by Bonferroni post-hoc test. Results: The LSA extract significantly inhibited both α-amylase and α-glucosidase enzymes with the IC 50s of 1.21±0.16 and 49.71±0.86 µg/mL, respectively. Meanwhile, the LSE extract selectively inhibited α-amylase activity (IC 50 = 22.21±4.00 µg/mL) with no apparent inhibition against α-glucosidase activity. Both LSA and LSE extracts inhibited α-amylase enzyme in a mixed inhibition manner whilst the LSA extract also acted as a mixed inhibitor against α-glucosidase enzyme. The extracts possessed higher binding affinities toward the enzymes, indicated by the lower K i values, when compared to acarbose (positive control). Conclusion: These results suggest the potential use of the extracts for a control of postprandial plasma glucose.

Introduction: The biofilm formation capability of Enterococcus faecalis is one of the key virulence factors contributing to its multidrug resistance and therapeutic challenges. Lupinifolin, a prenylated flavanone extracted from the stems of Derris reticulata Craib., possesses antibacterial properties against a range of gram-positive cocci. This study aimed to investigate the effects of lupinifolin alone or in combination with vancomycin against E. faecalis biofilm formation at different incubation durations, presumably representing different biofilm stages. Methods: The crystal violet biofilm formation assay and the micro-broth dilution method were used to measure the antibiofilm and antibacterial activities, respectively. Results: Lupinifolin did not inhibit E. faecalis growth at the highest concentration tested, i.e., minimum inhibitory concentration (MIC) > 128 µg/mL. However, lupinifolin at the sub-MICs (16-128 µg/mL) possessed a significant inhibition against E. faecalis biofilm formation at every incubation time of 6, 12, 24, and 36 hours. Lupinifolin had the lowest median inhibitory concentrations (IC50) of 6.78 ± 3.04 µg/mL after incubation for 6 hours. Thus, the antibiofilm action of lupinifolin was most likely produced predominantly at the first stage of biofilm formation, known as initial surface attachment. The sub-MICs of lupinifolin also significantly enhanced the antibiofilm activity of vancomycin at relatively low concentrations of ¼ MIC (2 µg/mL) and 1 / 8 MIC (1 µg/mL), specifically at 6- and 36-hour incubation (P<0.05). Conclusion: These results point to lupinifolin’s potential use against E. faecalis as an antibiofilm agent. Nonetheless, more research is needed to identify the exact antibiofilm mechanism of lupinifolin.