Antibacterial and antioxidant activities of methanolic extract of Sterculia tragacantha Lindl from Cameroon

Introduction :The constant increase of gastrointestinal infections prevalence associated with the pathogenesis of reactive oxygen species (ROS) linked to such diseases and therapeutic failure have warranted the search for plants with antibacterial and antioxidant properties becomes primordial (Fotsing et al., 2020).The aim of the present study was to investigate the antibacterial and antioxidant activities of the methanol extract from Sterculia tragacantha) Stem bark.
Methods : The stem bark of Sterculia tragacantha were harvested at Mbanga, locality of Mungo Division (Littoral Region). The extract was prepared by maceration of dried powder using methanol. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) tests were conducted with a modified rapid piodonitrotetrazolium chloride (INT) colorimetric assay (CLSI, 2015). Subsequently, antioxidant activities of the extract were primarily investigated in vitro by 2.2-diphenyl-1-pycrazylhydrazyl (DPPH) and 2.2′-Azino-bis (3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activities and Ferric reducting antioxidant power (FRAP) reductive assays while ex vivo antioxidant activity was assessed by evaluating the oxidative stress biochemical parameters (SOD, CAT, MDA) of sheep red blood cells after treatment. Extract was subjected to chemical screening). Phytochemical screening was performed according to standards protocols (Harbone, 1973), while total phenolic and flavonoïds contents were determined according to Folin-Ciocalteu and Aluminium Chloride colorimetric assay methods respectively.
Results : In vitro antibacterial activities were observed against all the tested bacteria (MIC = 32–1024μg/). The activity of the extract was, however, very weak compared to the reference antibiotic (MIC = 0.125– 128μg/mL). In addition, the extract showed good antioxidant potential and also a high reducing power comparable to standard used. Extract after treatment at 200 µg/mL reduced MDA levels and increased SOD, Catalase in oxidazed sheep red blood cells compared to neutral controls. Phytochemical assays revealed that crude extract contained alkaloids, phenols, flavonoïds, triterpenes and sterols while quantitative analysis shows a total phenolic and flavonoïd content of 1254,68±49 mg EAG/100 g and 304,30±11,82 mg EQ/100g of extract respectively.
Conclusion : All these results provide promising baseline information for the potential use of this plant in the treatment of gastroenteritis diseases and oxidative stress.
Keywords: Antibacterial, Antioxidant, Sterculia tragacantha, Gastroenteritis, Oxydative stress