Bacterial infections are responsible for a large number of deaths every year worldwide. On average, 80% of the African population cannot afford conventional drugs. Moreover, many synthetic antibiotics are associated with side effects and progressive increase in antimicrobial resistance. Currently, there is growing interest in discovering new antibacterial agents from ethnomedicinal plants. About 60% of the population living in developing countries depends on herbal drugs for healthcare needs. This study involved the screening of Centella asiatica commonly used by herbal medicine practitioners in Kisii County to treat symptoms related to bacterial infections. Standard bioassay methods were applied throughout the study. They included preliminary screening of dichloromethane: methanolic extract of Centella asiatica against human pathogenic bacteria including Salmonella typhi ATCC 19430, Escherichia coli ATCC 25922, Shigella sonnei ATCC 25931, Bacillus subtilis ATCC 21332, and Staphylococcus aureus ATCC 25923 using agar disc diffusion, broth microdilution method, and time-kill kinetics with tetracycline as a positive control. Phytochemical screening was carried out to determine the different classes of compounds in the crude extracts. Data were analyzed using one way ANOVA and means separated by Tukey’s test. Dichloromethane: methanolic extract of Centella asiatica was screened against the selected bacterial strains. Time-kill kinetic studies of the extracts showed dose- and time-dependent kinetics of antibacterial properties. Phytochemical screening of the DCM-MeOH extract revealed the presence of alkaloids, flavonoids, phenolics, terpenoids, cardiac glycosides, saponins, steroids, and tannins. The present study indicates that the tested plant can be an important source of antibacterial agents and recommends that the active phytoconstituents be isolated, identified, and screened individually for activities and also subjected further for in vivo and toxicological studies.

The root and leaf extracts of Launaea cornuta have been locally used in traditional medicine for decades to manage inflammatory conditions and other oxidative-stress-related syndromes; however, their pharmacologic efficacy has not been scientifically investigated and validated. Accordingly, we investigated the in vitro antioxidant activity, anti-inflammatory ( in vitro, ex vivo, and in vivo) efficacy, acute oral toxicity, and qualitative phytochemical composition of the aqueous root extract of L. cornuta. The ferric-reducing antioxidant power (FRAP) and the 2,2-diphenyl-2-pycrylhydrazyl (DPPH) radical scavenging test methods were used to determine the studied plant extract’s antioxidant activity. Besides, the anti-inflammatory efficacy of the studied plant extract was investigated using in vitro (anti-proteinase and protein denaturation), ex vivo (membrane stabilization), and in vivo (carrageenan-induced paw oedema in Swiss albino mice) methods. The studied plant extract demonstrated significant in vitro antioxidant effects, which were evidenced by higher DPPH radical scavenging and FRAP activities, in a concentration-dependent manner ( p < 0.05). Generally, the studied plant extract exhibited significant in vitro, ex vivo, and in vivo anti-inflammatory efficacy, respectively, and in a concentration/dose-dependent manner compared with respective controls ( p < 0.05). Moreover, the studied plant extract did not cause any observable signs of acute oral toxicity, even at the cut-off dose of 2000 mg/Kg BW (LD50 > 2000 mg/Kg BW), and was thus considered safe. Additionally, qualitative phytochemistry revealed the presence of various antioxidant- and anti-inflammatory-associated phytochemicals, which were deemed responsible for the reported pharmacologic efficacy. Further studies to characterise bioactive molecules and their mode(s) of pharmacologic efficacy are encouraged.

Background Arsenic poisoning affects millions of people. The inorganic forms of arsenic are more toxic. Treatment for arsenic poisoning relies on chelation of extracellularly circulating arsenic molecules by 2,3-dimecaptosuccinic acid (DMSA). As a pharmacological intervention, DMSA is unable to chelate arsenic molecules from intracellular spaces. The consequence is continued toxicity and cell damage in the presence of DMSA. A two-pronged approach that removes extracellular arsenic, while protecting from the intracellular arsenic would provide a better pharmacotherapeutic outcome. In this study, Coenzyme Q10 (CoQ10), which has been shown to protect from intracellular organic arsenic, was administered separately or with DMSA; following oral exposure to sodium meta-arsenite (NaAsO2) – a very toxic trivalent form of inorganic arsenic. The aim was to determine if CoQ10 alone or when co-administered with DMSA would nullify arsenite-induced toxicity in mice. Methods Group one represented the control; the second group was treated with NaAsO2 (15 mg/kg) daily for 30 days, the third, fourth and fifth groups of mice were given NaAsO2 and treated with 200 mg/kg CoQ10 (30 days) and 50 mg/kg DMSA (5 days) either alone or in combination. Results Administration of CoQ10 and DMSA resulted in protection from arsenic-induced suppression of RBCs, haematocrit and hemoglobin levels. CoQ10 and DMSA protected from arsenic-induced alteration of WBCs, basophils, neutrophils, monocytes, eosinophils and platelets. Arsenite-induced dyslipidemia was nullified by administration of CoQ10 alone or in combination with DMSA. Arsenite induced a drastic depletion of the liver and brain GSH; that was significantly blocked by CoQ10 and DMSA alone or in combination. Exposure to arsenite resulted in significant elevation of liver and kidney damage markers. The histological analysis of respective organs confirmed arsenic-induced organ damage, which was ameliorated by CoQ10 alone or when co-administered with DMSA. When administered alone, DMSA did not prevent arsenic-driven tissue damage. Conclusions Findings from this study demonstrate that CoQ10 and DMSA separately or in a combination, significantly protect against arsenic-driven toxicity in mice. It is evident that with further pre-clinical and clinical studies, an adjunct therapy that incorporates CoQ10 alongside DMSA may find applications in nullifying arsenic-driven toxicity.

Overproduction of free radicals in excess of antioxidants leads to oxidative stress which can cause harm to the body. Conventional antioxidants have drawbacks and are believed to be carcinogenic. The present study seeked to confirm folklore use and validate the antioxidant potentials of Grewia tembensis and Xerophyta spekei which have been widely used in the Mbeere community as medicinal plants. Antioxidant properties were determined through scavenging effects of diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide radicals as well as iron chelating effects. The data obtained was assayed in comparison to the standards (Ascorbic acid and EDTA). Ascorbic acid had a significantly greater DPPH radical scavenging property with an inhibitory concentration (IC50) value of 20.54 ± 2.24 µg/mL in comparison to the plant extracts, which had IC50 values of 33.00 ± 1.47 µg/mL, 69.66 ± 1.01 µg/mL and 86.88 ± 2.64 µg/mL for X. spekei, G. tembensis leaf and G. tembensis stem bark extracts, respectively. EDTA demonstrated a significantly greater iron chelating effect having a significantly lesser IC50 value of 25.05 ± 0.79 µg/mL as opposed to 43.56 ± 0.46 µg/mL, 89.78 ± 0.55 µg/mL, and 120.70 ± 0.71 µg/mL for X. spekei, G. tembensis leaf, and G. tembensis stem bark extracts respectively. Additionally, ascorbic acid also exhibited stronger hydrogen peroxide radical scavenging effect than the studied extracts. Generally, X. spekei extract had higher antioxidant activities as compared to both the leaf and stem bark extracts of G. tembensis. The phytochemical screening demonstrated the presence of secondary metabolites associated with antioxidant properties. The present study therefore, recommends ethno medicinal and therapeutic use of G. tembensis and X. spekei in the treatment and management of oxidative stress related infections.

Bacterial diseases are a leading cause of mortality and morbidity globally. During bacterial diseases, an elevation of host immune response occurs, which involves the production of free radicals in response to the bacterial infection. The overproduction of free radicals in excess of the antioxidants leads to oxidative stress. Conventional antibiotics are linked to side effects such as hypersensitivity reactions in addition to bacterial pathogens developing resistance against them. Artificial antioxidants are said to be carcinogenic. This study sought to confirm folklore use and validate the antibacterial and antioxidant potential of Senna singueana which has been widely used in the Mbeere community. The in vitro antibacterial potentials of the plant extract were investigated on Bacillus subtilis ATCC 21332, Escherichia coli ATCC 25922, Salmonella typhi ATCC 1408, and Staphylococcus aureus ATCC 25923. Ciprofloxacin (100 µg/ml) drug was used as a standard reference, whereas 5% DMSO was used as a negative reference. The antibacterial tests included disc diffusion and minimum inhibitory and bactericidal concentrations. S. singueana ethyl acetate extract showed broad-spectrum potential against tested bacterial microbes producing mean zones of inhibition (MZI) from 07.67 ± 0.33 to 17.67 ± 0.33 mm. The extract demonstrated a greater effect on Gram-positive than Gram-negative bacterial pathogens. Antibacterial properties of ciprofloxacin were significantly greater in comparison to plant extract in all the dilutions ( p < 0.05 ), while 5% DMSO was inactive against all the tested bacteria. MBC values were greater than MIC values. Antioxidant properties of the extract were determined through scavenging effects of DPPH and hydroxyl radicals (•OH) as well as ferric reducing antioxidant potential (FRAP) assay. S. singueana demonstrated effects against all radicals formed. Additionally, the extract exhibited ferric reducing abilities. The extract also contained various phytocompounds with known antibacterial and antioxidant properties. This study recommends the therapeutic use of S. singueana as an antibacterial as well as an antioxidant agent.