Search

Ethnopharmacological Relevance: Himatanthus drasticus is an important medicinal plant whose latex is traditionally used in Northeast Brazil to treat various diseases, including diabetes. The use of α-amylase and α-glucosidase inhibitors can be an effective strategy to modulate levels of postprandial hyperglycemia via control of starch metabolism., Aims of the Study: This study aimed to verify if H. drasticus latex has inhibitory activity against enzymes linked to type 2 diabetes, besides chemically characterizing the metabolites responsible for such activities. In addition, in silico analysis was performed to support the traditional claim of possible antidiabetic activity of this latex., Materials and Methods: Latex from H. drasticus stems was sequentially partitioned with n-hexane (FHDH), CHCl 3 (FHDC) and EtOH (FHDHA). Wash extraction of the FHDHA fraction was performed to obtain the other extract fractions. The FHDHA was submitted to chromatography in a SPE C 18 cartridge using gradient elution with MeOH/H 2 O to produce five fractions: FHDHA1, FHDHA2, FHDHA3, FHDHA4 and FHDHA5. The FHDHA1 was subjected to semi-preparative reverse phase HPLC. Lineweaver-Burk plots were used to investigate the kinetic parameters of α-amylase and α-glucosidase inhibitory activity. The interactions between plumieride and porcine pancreatic α-amylase and α-glucosidase were analyzed through an in silico molecular docking study., Results: Phytochemical identification of compounds present in the FHDHA fraction of H. drasticus latex was possible by 1H, 13C NMR analysis and mass spectrometry, and the results were compared with the literature. The identified compounds were α-ethyl glucoside, protocatechuic acid, 3-O-caffeoylquinic acid, 15-demethylplumieride acid, 5-O-caffeoylquinic acid, caffeic acid, vanillic acid, plumieride, and catechin. The inhibition results of the fractions tested against α-amylase and α-glucosidase showed inhibitory activities dependent on the increase of fractions and compound concentrations. The IC 50 results obtained from FHDHA, FHDHA1 and plumieride fractions against α-amylase were 36.46, 72.61, 33.87 μg/mL respectively. The IC 50 of plumieride was the closest to that of acarbose (22.52 μg/mL), a result similar to that obtained for α-glucosidase. The type of inhibition was competitive for both enzymes., Conclusions: There was strong inhibition of α-amylase and α-glucosidase by FHDHA, FHDHA1 and plumieride, suggesting that these enzymes slow glucose absorption., Competing Interests: Declaration of competing interest The authors report no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The chemical composition of the essential oils from aerial parts of Pectis apodocephala and Pectis oligocephala were analyzed by GC-MS. The essential oils of these species were predominantly constituted by monoterpenes. Geranial (42.9-44.5%), neral (32.2-34.2%) and alpha-pinene (10.7-11.4%) were the main constituents in the oil of P. apodocephala, while p-cymene (50.3-70.9%) and thymol (24.4-44.7%), were the prevalent compounds in the oil of P. oligocephala. The essential oils were tested against the root knot nematode Meloidogyne incognita and Aedes aegypti larvae survival. The results obtained show that both essential oils exhibited significant activity and could be considered as potent natural namaticidal and larvicidal agents.

The ethanolic extract of the fruit bark from Magonia glabrata yielded shikimic acid, scopoletin, sitosterol glycoside and 2-O-methyl-l-inositol. Antioxidant, icthyotoxicity and brine shrimp lethality activities were observed in this extract. The major constituent, 2-O-methyl-l-inositol, was found to be inactive in two assays but showed moderate activity as a radical scavenger.