Constituents of Huberantha jenkinsii and Their Biological Activities

Abstract

The phytochemical investigation of Huberantha jenkinsii resulted in the isolation of two new and five known compounds. The new compounds were characterized as undescribed 8-oxoprotoberberine alkaloids and named huberanthines A and B, whereas the known compounds were identified as allantoin, oxylopinine, N-trans-feruloyl tyramine, N-trans-p-coumaroyl tyramine, and mangiferin. The structure determination was accomplished by spectroscopic methods. To evaluate therapeutic potential in diabetes and Parkinson's disease, the isolates were subjected to assays for their α-glucosidase inhibitory activity, cellular glucose uptake stimulatory activity, and protective activity against neurotoxicity induced by 6-hydroxydopamine (6-OHDA). The results suggested that mangiferin was the most promising lead compound, demonstrating significant activity in all the test systems.

Keywords: Huberantha jenkinsii; Parkinsonism; diabetes; glucose uptake; α-glucosidase.

Figure 1

Chemical structures of compounds 1–7 isolated from Huberantha jenkinsii.

Figure 2

COSY (bold line), NOESY (double arrow line), and HMBC (arrow line) correlations observed for 1.

Figure 3

COSY (bold line), NOESY (double arrow line), and HMBC (arrow line) correlations observed for 2.

Figure 4

(a) Cell viability (● = 24 h incubation with test sample without 6-hydroxydopamine (6-OHDA)) and (b) cell survival (■ = 2 h incubation with 6-OHDA after 1 h of pretreatment with test sample); * A p < 0.05 is considered to be significantly different from the negative control (6-OHDA 100 µM); # less than 80% cell viability is considered cytotoxic; (−) = negative control (6-OHDA 100 µM); (+) = positive control (6-OHDA 100 µM and oxyresveratrol 50 µM).

Figure 5

Cytotoxicity (a) and glucose uptake stimulation (b) of compounds from H. jenkinsii. * (p < 0.05) Significantly different when compared to the control (DMSO); Ins = insulin (positive control).