Mitragyna diversifolia is an evergreen shrub or small tree that grows up to 5 m in height, found in moist and wet forests, as well as in disturbed habitats. Aavailable phytochemical studies suggested that the main constituents of M. diversifolia are triterpenoids and alkaloids.

In a study published in Biomedicine & Pharmacotherapy, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences isolated compounds from the branches of Mitragyna diversifolia and investigated their potential antidiabetic and antioxidant activities.

They isolated 16 compounds, including 12 triterpenoids (1–12), one phenolic compound (13), and three flavonoids (14–16).

"Compounds 1–7, and 10–16 were isolated from M. diversifolia for the first time," said ZHANG Yumei, corresponding author of this study and a researcher from XTBG.

Previous studies have shown that inhibiting the activity of α-glucosidase and increasing glucose uptake by organs or tissues are important strategies for type 2 diabetes mellitus (T2DM) patients to maintain appropriate blood glucose levels. 

The researchers evaluated the bioactivities of those compounds with α-glucosidase inhibition assay, molecular docking experiment, and glucose uptake experiment.

They identified the diabetes-related target proteins using a web-based pharmacological analysis platform. Two candidate targets, albumin (ALB) and peroxisome proliferator activated receptor gamma (PPARG), were then identified to be possibly related to its therapeutic effects.

The researchers found that compounds isolated from branches of Mitragyna diversifolia showed significant antidiabetic and antioxidant activities.

In particular, compounds 7, 14, and 15 exhibited potent inhibitory effects on α-glucosidase, and compound 14 was able to significantly promote glucose uptake rate in 3T3-L1 adipocytes. Moreover, compounds 13, 14, 15, and 16 also displayed strong antioxidant capacity.

"Our study revealed the specific antidiabetic and antioxidant substances of M. diversifolia, and indicated that compound 15 might be developed as a potential natural antidiabetic and antioxidant drug," said ZHANG Yumei.

Mitragyna diversifolia (Image by ZHU Renbin)