Phytochemical Constituents Isolated From Distichochlamys citrea M.F. Newman Rhizomes and Their Antioxidant and α-glucosidase Inhibitory Activities

Abstract

Objective/Background: Distichochlamys citrea M.F. Newman (Zingiberaceae) is an endemic plant of Vietnam and has been used as a folk medication for treatments of infection-related diseases, diabetes, and used as spice. This study aimed to characterize the antioxidant and α-glucosidase inhibitory activities of isolated compounds from D. citrea rhizomes. Methods: Compounds have been isolated from D. citrea rhizomes by different chromatographic techniques. Their chemical structures were determined based on mass spectrometry and nuclear magnetic resonance spectroscopy in comparison with those reported in the literature. The antioxidant effect was evaluated by 2,2-diphenyl-1-picrylhydrazyl-free radical neutralization whereas α-glucosidase inhibitory activity was determined by using the method of optical density measurement. Results: Seven compounds including 5-hydroxy-3,7,4'-trimethoxyflavone (1), kaempferol (2), platyphyllone (3), 5- O-caffeoylquinic acid (4), a mixture of phytosterols ( β-sitosterol (5) and stigmasterol (6)), and glycerol monostearate (7) were isolated and identified from D. citrea rhizomes. Compounds 1 and 2 simultaneously exhibited antioxidant activities (IC50 = 794.71 ± 2.68 µM, 14.08 ± 5.60 µM, respectively) and α-glucosidase inhibitory effects (IC50 = 189.40 ± 1.55 µM, and 31.86 ± 5.38 µM, respectively). Meanwhile, compound 3 and the mixture of 5 and 6 singly inhibited the enzyme α-glucosidase (IC50 = 69.41 ± 6.11 µM, 1204.82 µM, respectively), and showed weak antioxidant effects. On the contrary, compound 4 only had antioxidant activity (IC50 = 30.20 ± 1.86 µM). Compound 7 did not exhibit either antioxidant or enzymatic inhibitory effects. Conclusion: This is the first time that all of the seven compounds (1-7) and their biological activities were reported from D. citrea. Moreover, the α-glucosidase inhibitory effect of platyphyllone (3) is reported for the first time in the literature. This study revealed that flavonoids, phenolics, sterols, and monoglycerides in D. citrea rhizomes could be responsible for the antioxidant property and α-glucosidase inhibitory effect of this Vietnamese endemic medicinal plant.

Essential Oils ofDistichochlamys benenica: Chemical Constituents, Mosquito Larvicidal and Antimicrobial Activities

“…Hoang et al 32 reported the major components of the EO collected from D. benenica rhizomes in Quang Nam, Vietnam, which included 1,8-cineole (54.39% of the total chemical composition), β-pinene (7.50%), geranial (7.26%), and neral (6.79%). Interestingly, the present study yielded different results compared to those reported by Hoang et al 32 Specifically, we found geranyl acetate to be the most abundant component in the rhizome EO, whereas it was not detected in the rhizome EO studied by Hoang et al 30 Moreover, the concentration of 1,8-cineole was higher in Hoang et al's study of the rhizome EO than in our study. 32 These differences may be attributed to variations in the plant organs used, as well as geographical and environmental factors.…”

“…25 Several recent studies have focused on the phytochemical composition and bioactive properties of Distichochlamys species. [28][29][30][31] Additionally, investigations have been conducted into the chemical composition and biological activity of EOs derived from the leaves and rhizomes of D. citrea, D. orlowii, and D. benenica. [32][33][34][35][36][37] Notably, a study by Hoang et al 32 demonstrated the acetylcholinesterase activity of D. benenica rhizome EO collected from Quang Nam, Vietnam.…”

A Comparative Study of Chemical Profiling and Bioactivities between Thai and Foreign Hemp Seed Species (Cannabis sativa L.) Plus an In-Silico Investigation

“…Furthermore, in the current study, we performed molecular docking and a re-scoring docking function of all major components based on the GC–MS to evaluate a different energetical pattern between free and esterified fatty acids. Previous reports showed that free fatty acids exhibited more potent inhibitory activity against α-glucosidase than ester forms [ 30 , 50 , 51 ]. Our finding indicated that free fatty acids have lower energy (more stable) than their esters.…”