In Vitro Qualitative Phytochemical Screening, Tlc-Bioautography and Spot Screening of Bistorta Amplexicaulis (D.DON) Greene Extracts

The biological activities of Bistorta amplexicaulis (D.Don) Greene rhizome and leaves extracts were evaluated. In vitro antibacterial activity, direct bioautography, and spot screening of TLC developed bands were investigated against seven bacterial pathogens. Screening of phytochemical constituents was also done through both qualitative and thin layer chromatographic methods. DMSO extracts of rhizome indicated high sensitivity (12.33 ± 1.52 and 11.33 ± 0.57 mm) against Escherichia coli. Whereas methanolic and acetonic extracts of rhizome indicated significant inhibition (11.66 ± 1.15 and 11.33 ± 0.57 mm) of S. marcesscens. All leaf extracts revealed low sensitivity against E. coli. TLC-bioautography and spot screening methods showed the significant use of B. amplexicaulis as an antibacterial agent. Antioxidant activity indicated that acetone and DMSO extracts of rhizome and methanolic leaf extract have maximum scavenging potential. Among the screened phytochemicals, terpenoids, phenols, and quinones were detected in all extracts indicating the potential use of B. amplexicaulis as both antibacterial and antioxidant agents. Bangladesh J. Bot. 50(3): 613-622, 2021 (September)

ANTIBACTERIAL ACTIVITY OF ROBUSTA COFFEE (Coffea robusta L.) PEEL EXTRACT AGAINST HUMAN PATHOGENIC BACTERIA

Now in these days infectious diseases seriously affect human health and sometimes these infections might become the cause of human mortality. Most of these infectious diseases are caused by bacteria, viruses, and fungi. Although large numbers of antibiotics are available increasing drug resistance in these microorganisms became a serious matter of concern in the scientific community. There is an urgent need for research on alternate natural products that can manage these pathogenic microorganisms without inducing any resistance. The purpose of this study was to determine the antibacterial activity of Robusta coffee (Coffea robusta L.) fruit peel extract against 5 human pathogenic bacteria i.e. Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Salmonella thypi NCTC 786. The sample was extracted using the maceration method with methanol as the solvent. The antibacterial activity of fruit peel extract was determined by using the agar diffusion method while the presence of active ingredients was determined by the using TLC-Bioautography assay performed using the mobile phase of n-hexane: ethyl acetate (1 : 3). The results of the study revealed significant antibacterial activity of coffee peel extract against E. coli and B. subtilis with an inhibition zone of 10.15 mm and 10.96 mm, respectively. Furthermore, results of the TLC-Bioautography revealed that the compounds at Rf 0.76 inhibit the growth of E. coli and the compounds at Rf 0.27 inhibit the growth of B. subtilis bacteria. These active spots were suspected to be flavonoid and phenolic compounds, respectively but further confirmation detail study is required in the future.

An Evolving Technology That Integrates Classical Methods with Continuous Technological Developments: Thin-Layer Chromatography Bioautography

Thin-layer chromatography (TLC) bioautography is an evolving technology that integrates the separation and analysis technology of TLC with biological activity detection technology, which has shown a steep rise in popularity over the past few decades. It connects TLC with convenient, economic and intuitive features and bioautography with high levels of sensitivity and specificity. In this study, we discuss the research progress of TLC bioautography and then establish a definite timeline to introduce it. This review summarizes known TLC bioautography types and practical applications for determining antibacterial, antifungal, antitumor and antioxidant compounds and for inhibiting glucosidase, pancreatic lipase, tyrosinase and cholinesterase activity constitutes. Nowadays, especially during the COVID-19 pandemic, it is important to identify original, natural products with anti-COVID potential compounds from Chinese traditional medicine and natural medicinal plants. We also give an account of detection techniques, including in situ and ex situ techniques; even in situ ion sources represent a major reform. Considering the current technical innovations, we propose that the technology will make more progress in TLC plates with higher separation and detection technology with a more portable and extensive scope of application. We believe this technology will be diffusely applied in medicine, biology, agriculture, animal husbandry, garden forestry, environmental management and other fields in the future.

ANTIBACTERIAL ACTIVITY AND TLC-BIOAUTOGRAPHY ANALYSIS OF THE ACTIVE FRACTIONS OF Muntingia calabura L. LEAVES AGAINST Staphylococcus aureus

This study aims to determine the antibacterial activity and TLC-bioautography profile of the active fractions of Muntingia calabura L. leaves against Staphylococcus aureus. Muntingia calabura L. leaves were macerated with ethanol 96% then fractionated with n-hexane, ethyl acetate, and methanol solvent, respectively. The antibacterial activity was tested by the Kirby-Bauer method to determine the most active fraction and the lowest concentration that inhibited the growth of Staphylococcus aureus. TLC-bioautography was tested using chloroform: ethyl acetate (2:8) as the mobile phase and silica gel F254 as the stationary phase. Antibacterial activity test of n-hexane and ethyl acetate fractions at a concentration of 10% w/v showed activities with inhibition zone diameter of 0.33±0.288 and 9.66±5.77 mm, respectively. At the same time, the methanol fraction showed no activity. The lowest concentration of ethyl acetate fraction which still showed the inhibition zone was 0.312% w/v. The TLC-bioautography profile showed active spots with an Rf value of 0.82 and had an inhibitory zone diameter of 4.013±0.864 mm. It can be concluded that the ethyl acetate fraction was the most active fraction that inhibited the growth of Staphylococcus aureus and had one active spot on the bioautography test.