In-vitro and In-vivo studies on antibacterial activity of Ocimum tenuiflorum (Kalo tulshi), Nigella sativa (Kalo zira) and Tinospora cordifolia (Gulancha) extracts against some human pathogenic strains

Abstract

Background of the study: Plant-derived medicines have been used as part of traditional healthcare for thousands of years. More than 80% of the population in developing countries depend on plants for their medical needs. A study conducted by Bregum F. (2010) showed that 84.1% of respondents in Bangladesh were using medicinal plants for their health ailments. However, only a few of these plants have been investigated for their antimicrobial properties, and the vast majority have not yet been adequately evaluated. Existing allopathic medicines have been observed to cause significant side effects while treating various diseases. In some cases, these side effects can even be life-threatening. Therefore, people are increasingly seeking treatments with fewer or no side effects, often turning to natural medicines to combat diseases. Nowadays, antibiotic resistance has become a serious and devastating public health problem worldwide, requiring immediate action in both developing and developed countries. Although it occurs naturally, the misuse of antibiotics in humans and animals is accelerating the process. A growing number of infections—such as pneumonia, urinary tract infections (UTIs), gastrointestinal (GI) disorders, gonorrhoea, skin and soft tissue infections (SSTIs), and salmonellosis—are becoming harder to treat with existing antibiotics. Antibiotic resistance leads to longer hospital stays, higher medical costs, and increased mortality. It has been shown that inappropriate dosing, incorrect quantities, repeated use of the same antibiotics, and evolving disease patterns contribute to the development of antibiotic resistance. Developing new active ingredients and natural antibiotics to combat resistant bacteria is a time-consuming process. This study is an attempt to develop natural antibiotics to combat bacterial infections and reduce the incidence of antibiotic resistance. Methodology: It was a laboratory based (in vitro) and experimental animal (in vivo) study. The in vitro and in vivo studies were conducted in Microbiology laboratory and Animal House of Institute of Nutrition & Food Science respectively. The ethanolic extract (20, 40 and 80 grams) of Tinospora cordifolia, Ocimum tenuiflorum and Nigella sativa were collected by maceration process. Pathogenic microorganisms such as Streptococcus pyogenes, Staphylococcus aureus, Salmonella typhi, Escherichia coli, Vibrio cholerae and Klebsiella pneumoniae were cultured in Muller Hinton Agar (MHA) media. The antibacterial assay was performed by well diffusion method. The IX average diameter of zone of inhibitions were recorded after 24 hours, 48 hours and 72 hours. For in vivo study, 10 μL/ 0.01ml of Staphylococcus aureus broth approximately 10 14 Colony Forming Units (CFU) were injected to Swiss Albino mice model by subcutaneous. Staphylococcal Skin & Soft Tissue Infections (SSTIs) were observed in and around the sites of injection. After 3 days of inoculation, the extracts were given orally in different dose depended manners like TC20, TC40, TC80, TC160, TC320, Levo 10 and Levo 20 twice daily to the Treatment Groups. After 7 days of treatment, mice blood samples were collected from vein of tail into culture tube. The samples were sent to microbiology laboratory with proper labelling for sero-culture. Results: In vitro antibacterial activities were measured as the maximum zone of inhibition (MZI) in millimeters (mm), and in vivo antibacterial activities were assessed by bacterial clearance from plasma. The alcoholic extract of Tinospora cordifolia (TC-80) showed the maximum zone of inhibition against Escherichia coli, Streptococcus pyogenes, Vibrio cholerae, Staphylococcus aureus, Klebsiella pneumoniae, and Salmonella typhi, respectively. The study also found that the maximum zone of inhibition was measured in Nigella sativa (NS-80) against Streptococcus pyogenes, Staphylococcus aureus, and Vibrio cholerae. Furthermore, the study demonstrated that Ocimum tenuiflorum (OT-80) exhibited significant antibacterial activity against Streptococcus pyogenes, Vibrio cholerae, and Staphylococcus aureus. In the in vivo study, it was observed that TC-20, TC-40, and TC-80 did not show significant antibacterial effects against Staphylococcus aureus, but TC-160 and TC-320 exhibited significant antibacterial activity against Staphylococcus aureus after 7 days of administration. Conclusion: The in vitro study revealed that the ethanolic extract of Tinospora cordifolia has a significant antibacterial effect against Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Vibrio cholerae, Klebsiella pneumoniae, and Salmonella typhi. The in vivo study demonstrated that lower concentrations (20, 40, 80) of Tinospora cordifolia did not show in bacterial clearance from plasma against Staphylococcus aureus, while higher concentrations (160 and 320), administered twice daily, showed significant bacterial clearance from plasma after 7 days of oral administration.