Chemical Constituents of Clerodendrum splendens (Lamiaceae) and Their Antioxidant Activities

The purpose of this study was to evaluate the antioxidant activity of compounds isolated from Clerodendrum splendens leaves. The leaves of Clerodendrum splendens are used in traditional medicine by indegenous people to treat shingles, spleen in children, asthma, rheumatism, ulcers and malaria. In vivo and in vitro studies carried out by many researchers have shown that Clerodendrum splendens has antioxidant properties. The chemical study of the methanol extract of Clerodendrum splendens leaves (Lamiaceae) led to the isolation of three compounds: Triancontanol (1), (22E, 24S) - Stigmasta - 5, 22, 25 - trien – 3β-ol(2); 3-O-D-glucopyranoside of (22E, 24S) - Stigmasta - 5,22,25 - trien - 3β-ol (3). Their structures were elucidated on the basis of a spectroscopic analysis and a comparison of their data spectral with those reported in the literature. The results of the antioxidant activity have shown that the compounds 1 and 2 inhibit the peroxidation of the hepatic lipids, they also show that the compounds 1, 2 and 3 have a reducing effect on Fe 2+ . However, the compounds 1, 2 and 3 have an OH reduction power which is directly proportional to the concentration of these compounds compared to that of vitamin C, which made it possible to determine the IC 50 of the different compounds. Furthermore, the compounds 1 and 2 have higher IC 50 than that of vitamin C (5.613 ± 0.117). The results of this study suggest that Clerodendrum splendens represents an untapped source of compounds with potential antioxidant activity that could be explored in the development of new therapeutic natural products.