Traditionally used Thai medicinal plants: In vitro anti-inflammatory, anticancer and antioxidant activities

Aims of the studyIn order to assess traditional Thai claims about the therapeutic potential of medicinal plants and to select plants for future phytochemical research, nine plant species with anti-inflammatory uses were selected from Thai textbooks and assessed for their in vitro anti-inflammatory, antiproliferative and antioxidant activities.MethodsNuclear factor-kappaB (NF-κB) inhibitory effects in stably transfected HeLa cells were determined by luciferase assay, and effects on LPS-induced pro-inflammatory mediators prostaglandin E2 (PGE2), interleukin (IL)-6, IL-1β, and tumour necrosis factor (TNF)α in primary monocytes were assessed by ELISA. Cytotoxic activities were examined against HeLa cells, human leukaemia CCRF-CEM cells and the multidrug-resistant CEM/ADR5000 subline using the MTT and XTT tests. However, a redox status has been linked with both inflammation and cancer, antioxidant effects were also assessed using the DPPH, lipid-peroxidation, and Folin-Ciocalteau methods.ResultsAmong all the nine species, Gynura pseudochina var. hispida and Oroxylum indicum showed the most promising NF-κB inhibitory effects with the lowest IC50 values (41.96 and 47.45 μg/ml, respectively). Muehlenbeckia platyclada did not inhibit the NF-κB activation but effectively inhibited the release of IL-6, IL-1β and TNF-α with IC50 values ranging between 0.28 and 8.67 μg/ml. Pouzolzia indica was the most cytotoxic against CCRF-CEM cells and the multidrug-resistant CEM/ADR5000 cells (9.75% and 10.48% viability, at 10 μg/ml, respectively). Rhinacanthus nasutus was the most potent cytotoxicity against HeLa cells (IC50 3.63 μg/ml) and showed specific cytotoxicity against the multidrug-resistant CEM/ADR5000 cells (18.72% viability at 10 μg/ml, p < 0.0001 when compared to its cytotoxicity against CCRF-CEM cells). Moreover, Oroxylum indicum showed a high level of antioxidant activity by inhibiting lipid-peroxidation (IC50 0.08 μg/ml).ConclusionsThis study provides in vitro evidence for the use of the Thai plants, most importantly Gynura pseudochina var. hispida, Oroxylum indicum and Muehlenbeckia platyclada as Thai anti-inflammatory remedies and these plants are now a priority for further phytochemical research.

In vitro anti-inflammatory, cytotoxicity, and antioxidant activities of nine anti-inflammatory remedies used traditionally in Thailand – Basella alba, Basella rubra (Basellaceae), Cayratia trifolia (Vitaceae), Gynura pseudochina var. hispida, Gynura pseudochina (Asteraceae), Muehlenbeckia platyclada (Polygonaceae), Oroxylum indicum (Bignoniaceae), Pouzolzia indica (Urticaceae), and Rhinacanthus nasutus (Acanthaceae) – allowed the selection of lead extracts for further ethnopharmacological research, most importantly Gynura pseudochina var. hispida.Figure optionsDownload as PowerPoint slide