Analysis of Antioxidant Phytochemicals and Anti-Inflammatory Effect from Vitex rotundifolia L.f

Abstract

An extraction method using 80% EtOH was selected and applied to obtain the total extracts from leaves, flowers, fruits, twigs, and roots of Vitex rotundifolia L.f. based on the antioxidant activity-guided experiments. Subsequently, total extract from each part of V. rotundifolia was successfully partitioned into fractions, which were evaluated for their antioxidant and anti-inflammatory properties via DPPH, ABTS, and NO assays, respectively. Among them, EtOAc (E) and n-butanol (B) fractions showed the potent antioxidant activity and the methylene chloride (MC) fractions of roots, leaves, and fruits that exhibited strong scavenging activity on DPPH and ABTS radicals. In the anti-inflammatory assay, n-hexane (H) and MC fractions of leaves potently inhibited NO production in LPS-stimulated RAW264.7 cells, followed by E fractions derived from fruits, flowers, twigs, and roots, along with B fractions from flowers and twigs. Additionally, a comprehensive HPLC-decoupled MS profiling was established and validated using seven isolated marker compounds (1-7), which were identified by analysis of their UV, NMR, and MS data. The established method was also applied for quantification of these marker compounds in each organ collected from different locations, and to assess their antioxidant capacity by a screening DPPH-HPLC method. Principal component analysis suggested the botanical organs from this plant correlated with the marker compound contents in association with bioactivity. The study results are a prelude to further studies involving the active fractions and provide a comprehensive insight into the functional products of this plant against oxidative diseases.

Keywords: DPPH-HPLC; NO production; Vitex rotundifolia; analytical method; antioxidant.

Figure 1

UV- and MS spectra of marker compounds (1–7).

Figure 2

Chemical structures of marker compounds 1–7 isolated from the leaves of V. rotundifolia.

Figure 3

Chromatograms detected at 254 nm of five organs [(A), leaves (L.), flowers (FL.), fruits (FR.), twigs (T.), roots (R.)], seven marker compounds (B), and DPPH-HPLC (C). Seven marker compounds: protocatechuic acid (1), chlorogenic acid (2), 4-hydroxybenzoic acid (3), orientin (4), agnuside (5), 6′-p-hydroxybenzoylmussaenosidic acid (6), and 3,5-di-CQA (7).