Phytochemical profiling, antioxidant, cytotoxic, and anti-inflammatory activities of Plectranthus rugosus extract and fractions: in vitro, in vivo, and in silico approaches

Inflammation is a key biological reaction that comprises a complex network of signals that both initiate and stop the inflammation process.

This study targets to evaluate the anti-inflammatory potential of the leaves of the Plectranthus rugosus (P. rugosus) plant involving both in vitro and in vivo measures. The current available drugs exhibit serious side effects. Traditional medicines impart an essential role in drug development. P. rugosus is a plant used in traditional medicine of Tropical Africa, China, and Australia to treat various diseases.

Lipopolysaccharide (LPS), an endotoxin, kindles macrophages to discharge huge quantities of pro-inflammatory cytokines like TNF-α and IL-6. So, clampdown of macrophage stimulation may have a beneficial potential to treat various inflammatory disorders. The leaves of the P. rugosus are used for swelling purpose by local population; however, its use as an anti-inflammatory agent and associated disorders has no scientific evidence.

The extracts of the plant Plectranthus rugosus ethanolic extract (PREE), Plectranthus rugosus ethyl acetate extract (PREAF), and the compound isolated (oleanolic acid) suppress the pro-inflammatory cytokines (IL-6 and TNF-α) and nitric oxide (NO), confirming its importance in traditional medicine.

The pro-inflammatory cytokines are inhibited by P. rugosus extracts, as well as an isolated compound oleanolic acid without compromising cell viability.