Bioactive constituents from Vitex negundo var. heterophylla and their antioxidant and α-glucosidase inhibitory activities

- Systematic phytochemical investigation of Vitex negundo var. heterophylla led to the isolation of twenty-four compounds.
- Four compounds were new and five others were obtained from Vitex genus for the first time.
- Six flavonoids showed more potent DPPH radical scavenging capacity than l-ascorbic acid.
- Isoorientin-6″-O-caffeate was an even more effective antioxidant and α-glucosidase inhibitor than the positive controls.

Vitex negundo L. var. heterophylla (Franch.) Rehd. is widely accepted as a functional and medicinal food in China because of the presence of bioactive components which improve the physical condition. In the present study, the bioactive constituents, antioxidant, α-glucosidase and DPP-IV inhibitory activities of V. negundo var. heterophylla were investigated. Two new coumarin glycosides, vitexnegheteroins I-J (1-2), and two new iridoid glycosides, vitexnegheteroins K-L (3-4), were isolated from the leaves and seeds of V. negundo var. heterophylla, together with twenty known compounds. Seven compounds presented stronger antioxidant activities than l-ascorbic acid in both DPPH and ABTS assays. Among them, isoorientin-6″-O-caffeate (22) also exhibited more potent α-glucosidase inhibitory activity than acarbose with an IC50 value of 0.24 ± 0.02 μM. These findings further revealed the bioactive components of this edible aromatic plant and disclosed the potency of it to be developed as new antioxidant and α-glucosidase inhibitory agents.

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