A screening of plants used in Colombian traditional medicine revealed the anti-inflammatory potential of Physalis angulata calyces

Abstract

The use of natural products by communities from the Colombian Caribbean region to treat health issues, together with biodiversity and geographical features, constitute a great scenery to develop new therapies based on ethnopharmacological heritage. Here, we investigated the anti-inflammatory potential of 10 commonly used plants in Colombian folk medicine, evaluating their effect on nitric oxide (NO) production by LPS-stimulated RAW 264.7 macrophages. The most active plant was evaluated in vivo using 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced mouse ear edema, along with its effect on the production of pro-inflammatory mediators in vitro. The extract of Physalis angulata L. calyces showed the highest activity. This extract was fractionated and its dichloromethane fraction (DF) was the most active in vitro, inhibiting the production of NO, prostaglandin E₂ (PGE₂), interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α and monocyte chemotactic protein (MCP)-1 (CCL2). In vivo, DF showed a significant inhibition of ear edema and myeloperoxidase (MPO) activity, with evident reduction of the leukocyte infiltration into tissue. Our results support the ethnopharmacological use of the selected plants in folk medicine. P. angulata dichloromethane fraction represents a promising source of pharmacological compounds with great potential therapeutic use to treat inflammatory illness.

Keywords: Anti-inflammatory; Folk medicine; Macrophages; Nitric oxide; Physalis angulata.

Fig. 1

In vivo evaluation of the anti-inflammatory effect of the extract and fractions obtained from the calyces of P. angulata in the TPA-induced mice ear edema. TE(1): Total extract (1 mg/ear), EF(1): Ether fraction (1 mg/ear), MF(1): Methanol fraction (1 mg/ear), DF(1): Dichloromethane fraction (1 mg/ear), DF(0,5): Dichloromethane fraction (0,5 mg/ear), Indo: Indomethacin. (A): Ear weight difference (mg) and inflammation inhibition percentage, circular 6 mm diameter sections of both treated and non-treated ear were weighted. (B): Enzymatic activity measured in ear tissue homogenized expressed as MPO units/mg tissue. Each value represents mean ± S.E.M. (n = 6) from at least two independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 compared with TPA group (One way ANOVA). &&&P < 0,001 compared with Control group (One way ANOVA).

Fig. 2

Histology samples from the TPA-induced ear edema test, ear tissue was dehydrated, embedded in paraffin and stained with Hematoxylin-Eosin. All pictures were taken in an Axio Lab A1 microscope (Zeiss, Oberkochen, Germany) and correspond to the 10X zoom. (A) Control group, (B) TPA group, (C) Indomethacin (0,5 mg/ear), (D) TE (1 mg/ear), (E) EF (1 mg/ear), (F) MF (1 mg/ear), (G) DF (1 mg/ear) and (H) DF (0,5 mg/ear).

Fig. 3

Effect of the dichloromethane fraction (DF) on the production of pro-inflammatory mediators by LPS-stimulated RAW 264.7 macrophages. (A): NO•, (B): PGE2, (C): IL-1 β, (D): IL-6, (E): TNF-α, (F): MCP-1. Cells were incubated for 24 hours after stimulation and treatment with DF. Then supernatants were collected and mediators were measured through ELISA kits, except the NO• which was measured with the Griess reaction, as described in Methods. Each value represents mean ± SEM (n = 6). *P < 0.05, **P < 0.01, ***P < 0.001 compared with LPS group (One way ANOVA).