Antimicrobial and antioxidant activity of acetone leaf extract of Senna Singueana

Abstract

Emergence of resistance among many commercially available antibiotics has dimmed all the efforts made in the antibacterial agent development. Many infections that results from bacteria exposure have as well resulted into development of other complications. The multidrug resistance has been ignited by misuse and improper use of the antibiotics. On the other hand the oxidation reaction in the body results into free radicals that have deleterious impact on the body. The increased concentration of these free radicals which are very reactive tend to attack the biomolecules resulting into damage and in some instances result into death of the cells or tissues. The increase free radicals results into a state of oxidative stress which is trigger in many conditions such as cancer, diabetes, neurodegenerative disorders and aging. The conventional medicines used in management of the bacterial infections and oxidative stress related conditions are expensive and in some cases have side effects and are less potent. Alternatives from plants have been identified as the savior to the current problems. Plants synthesized secondary metabolites that are pharmacologically active among many conditions. This has seen many plant being explored for their medicinal properties. Senna singueana has been widely used as an antimalarial agent in many countries including Kenya and Tanzania. This antimalarial property has been widely investigated by many researchers. However its antimicrobial and antioxidant activity is not well known. This study aimed at evaluating the antimicrobial and antioxidant activity of acetone leaves extract of Senna singueana. The antimicrobial activity was evaluated by the diffusion method employing the disc diffusion technique. The antimicrobial activity was investigated against four bacteria strains; three gram negative; Escherichia coli, Acinetobactor baumanni and Salmonella enteritidis and one gram positive Methicillin Resistant Staphylococcus aureas. The antioxidant property was investigated by monitoring its free radical scavenging property using the DPPH free radical. The zones of inhibition at 100 mg/ml concentration levels were 14.00±0.00 mm, 12.33±0.577 mm, 12.00±0.00 mm and 13.00±1.00 mm for Acinetobactor baumanni, Salmonella enteritidis, Escherichia coli and Methicillin Resistant Staphylococcus aureas respectively. Ciprofloxacin at 10 ug/ml recorded 30.00± 1.00 mm, 37.33±0.577 mm, 39.667±0.577 mm and 30.667±0.577 mm for Acinetobactor baumanni, Salmonella enteritidis, Escherichia coli and Methicillin Resistant Staphylococcus aureas. The antioxidant results showed that the acetone extract was significantly scavenged the DPPH free radicals at concentration levels 500 ug/ml, 250 ug/ml and 125 ug/ml. The activity at tis particular concentration levels was was comparaeble to L-ascorbic acid and no significant difference was noted between them (p>0.05). The antioxidant activity of the acetone extract at lower concentrations of 62.5 ug/ml, 41.25 ug/ml and 15.625 ug/ml was lower than the L-ascorbic acid. In conclusion Senna singueana is a potential antioxidant and antimicrobial agent and can be taken as an alternative to the conventional drugs