Anti-inflammatory, Analgesic, and Cytotoxic Effects of the Phytexponent Preparation: a Polyherbal Formulation

Abstract

Pain and inflammation are the commonest manifestations of various pathologies, and are associated with high morbidities, debility, and economic strife globally, especially in underdeveloped regions of sub-Saharan Africa. The currently available conventional analgesic and anti-inflammatory drugs cause serious side effects, some of which are life threatening, are unaffordable, and unavailable to all patients, especially in low-income countries, hence the need for better alternatives. In the current study, the in vivo anti-inflammatory, analgesic, and in vitro cytotoxic activities of the Phytexponent preparation comprising the ethanolic extracts of Viola tricolor, Echinacea purpurea, Allium sativum, Matricaria chamomilla, and Triticum repens were investigated. The carrageenan-induced paw oedema technique was adopted to investigate the anti-inflammatory activity of the Phytexponent in experimental mice, at doses of 15.625 mg/Kg BW, 31.25 mg/Kg BW, 62.5 mg/Kg BW, 125 mg/Kg BW, 250 mg/Kg BW and 500 mg/Kg BW, with Indomethacin (10 mg/Kg BW) as positive control drug. The paw sizes of respective animals were measured using a plethysmographic technique, and the values used to calculate the percentage reduction in oedematous paw size, as an indicator of anti-inflammatory activity of the Phytexponent. The acetic acid-induced writhing technique was used to determine the analgesic activity of the Phytexponent in experimental Swiss albino mice at similar doses as those used for anti-inflammatory assay and indomethacin (4 mg/Kg BW) as the reference drug. Then, the number of wriths were recorded and expressed as the percentage inhibition of writhing. The standard 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay technique was used to investigate the in vitro cytotoxic effects of the Phytexponent in Vero E6 cell line with cyclophosphamide as a positive cytotoxic agent. The percentage inhibitions of cell proliferation (percentage cytotoxicity) were determined according to a standard procedure. The study findings revealed that the Phytexponent preparation exerted significant anti-inflammatory effects in carrageenan-induced paw oedema mouse model, which ranged from 1.117±0.193% at the first hour to 11.162±0.091% at the fourth hour, at a dose of 31.25 mg/Kg BW, 6.240±0.242 % at the first hour to 17.407±0.186% at the fourth hour at a dose of 62.60 mg/Kg BW, 9.645±0.020% at the first hour to 31.795±0.090% at the fourth hourat a dose of 125 ,g/Kg BW, and 14.000±0.102% at the first hour to 37.931±0.133% in the fourth hour, at a dose of 250 mg/Kg BW (p<0.05). Notably, the Phytexponent significantly inhibited inflammation in a dose- and time-dependent manner (p<0.05). The Phytexponent preparation exhibited significant analgesic activity (p<0.05) in experimental mice as depicted by reduced writhing frequencies (high percentage inhibitions of acetic acid-induced writhing), which increased from 55.054±0.174% at a dose of 31.25 mg/Kg BW to 94.982±0.098% at a dose of 250 mg/Kg BW, in a dose-dependent manner (p<0.05). The Phytexponent exhibited significantly higher analgesic activity at doses of 125 mg/Kg BW (75.924±0.253%) and 250 mg/Kg BW (94.982±0.098%) than indomethacin (64.786±0.098%), indicating higher analgesic efficacy. The Phytexponent preparation was not cytotoxic to Vero E6 cells as indicated by high CC50 value (>1000 μg/ml) compared to cyclophosphamide (CC50= 2.48μg/ml). The present study indicated that the Phytexponent formulation has significant in vivo anti-inflammatory and analgesic activities in mice models and is not cytotoxic to Vero E6 cell line. Therefore, based on the study findings, the Phytexponent formulation is a potential source of safe analgesic and anti-inflammatory associated phytocompounds. Further empirical studies, determination of mode(s) of anti-inflammatory and xi analgesic efficacy, and safety of the Phytexponent and its bioactive phytochemicals should be undertaken.