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Abstract

This study reports the potential of Alternanthera sessilis leaves as antioxidant, antimicrobial, anti-inflammatory and anti-diabetic agent and also the characterization of a novel phytochemical from A. sessilis using bio-activity guided extraction. Antimicrobial property was studied against five bacterial pathogens, Escherichia coli (MTCC: 1687), Bacillus cereus (MTCC: 0430), Klebsiella pneumonia (MTCC: 7028), Staphylococcus aureus (MTCC: 3160), Proteus mirabilis (MTCC: 3310) and against two fungal pathogens, Aspergillus niger [MTCC 281] and Aspergillus flavus [MTCC 10938]. Petroleum ether extract of A. sessilis leaves demonstrated significant antimicrobial property and hence was further purified to identify its active phytochemicals. Silica-gel Column Chromatography followed by antimicrobial screening, lead to the identification of the active fraction, that was characterized by spectroscopic analyses. FT-IR, GC-MS and NMR (C 13 , and DEPT-45; 90; 135) analysis of the active fraction, characterized the phytochemical to be 3,3'-(propane-2, 2-diyl)-bis-(3,4,5,6,7,8-hexahydro-1Hisochromene) abbreviated as PDHC. To the best of knowledge, this is the first report of PDHC due to novelty in its chemical structure. In-silico molecular docking was performed for this identified compound to identify the possible mechanism of action. This study opens up opportunities for further research on this valuable anti-fungal phytochemical leading to possible treatment applications. INTRODUCTION: Medicinal plants are referred to as 'medicinal' or 'officinal' plants as it contains a ridiculous amount of secondary plant products. More than thousands of years, it has been well documented the medicinal uses of plants and different parts of the world still, rely on traditional medicines for treating different maladies 1. Medicinal plants are considered to be the "spine" of traditional medicine. In less developed nations, more than 3.3 billion individuals use medicinal plants continuously 2 .

The Genus Alternanthera: Phytochemical and Ethnopharmacological Perspectives

“…ex DC. as antidiabetic agent: Kumar and the team had used aqueous and ethanolic extracts of aerial parts ( Kumar S. M. et al, 2011 ); Tan and Kim had used hexane, ethyl acetate, and aqueous fractions of aerial parts ( Tan and Kim, 2013 ); Hossain and the team had used methanolic extract of aerial parts ( Hossain et al, 2014 ); Sundar and the team had used petroleum ether extract of leaves ( Sundar et al, 2019 ); Das and the team had used 95% ethanolic extract of the whole plant ( Das et al, 2015 ); Rao and the team had used ethanolic extract of the whole plant ( Rao et al, 2011 ); Manalo and the team had used n-hexane, ethyl acetate, and water fractions of the methanolic extract of leaves ( Manalo et al, 2020 ); Mohaimenul and the team had used ethanolic extract of aerial parts ( Mohaimenul et al, 2020 ); Tiwari and the team had used the juice ( Tiwari et al, 2013 ); Chai and the team had used hexane, chloroform, ethyl acetate, butanol, and aqueous fractions of methanolic extracts of leaves and callus ( Chai et al, 2016 ). Plenty of evidences obtained from the above researches leaved no doubt in that fact that Alternanthera sessilis (L.) R.Br.…”

“…ex DC. as anti-inflammatory agent: Sunmathi and the team had used ethanolic extract obtained from the leaves ( Sunmathi et al, 2016 ); Muniandy and the team had used 90% ethanolic extract of stems ( Muniandy et al, 2018a ); Sundar and the team had used petroleum ether and methanolic extracts of leaves ( Sundar et al, 2019 ); Kassuya and the team had used Ethanolic extract of whole plant (EEAT) as well as the isolated molecule, 2″-O-β-D-glucopyranosyl-vitexin ( Kassuya et al, 2021 ); Biella and the team had used aqueous extract of the whole plant ( Biella et al, 2008 ). Plenty of evidences obtained from the above researches leaved no doubt in that fact that Alternanthera sessilis (L.) R.Br.…”

“…ex DC. : Osuna and the team had used hexane and methanolic extracts obtained from the aerial parts ( Osuna et al, 2008 ); Jalalpure and the team had used petroleum ether (40–60°C), chloroform, acetone, methanolic, and aqueous extracts of leaves ( Jalalpure et al, 2008 ); Monroy and Limsiaco had used aqueous, ethanolic, and acetone extracts obtained from leaves ( Monroy and Limsiaco, 2016 ); Niraimathi and the team had used silver nanoparticles of aqueous extract of leaves ( Niraimathi et al, 2013 ); Rajamurugan and the team had used ethanolic extract obtained from the leaves ( Rajamurugan et al, 2013 ); D Suganya and the team had used aqueous extract of leaves and stems ( Suganya et al, 2019 ); Kota and the team had used petroleum ether, ethyl acetate, chloroform, and methanolic extract obtained from the leaves ( Kota et al, 2017 ); Sundar and the team had used petroleum ether and methanolic extracts of leaves ( Sundar et al, 2019 ); while Salvador and the team had used hexane and ethanolic extracts obtained from the adult plants ( Salvador et al, 2009 ). These studies clearly concluded that Alternanthera sessilis (L.) R.Br.…”

“…ex DC. : Borah and the team had used 90% methanolic, 70% acetone, 80% ethanolic extracts of leaves and stems ( Borah et al, 2011 ); Chai and the team had used hexane, chloroform, ethyl acetate, butanolic, and aqueous fractions of leaves and callus methanol extracts ( Chai et al, 2016 ); Sharma and the team 30% hydroethanolic extract of the whole plant ( Sharma et al, 2013 ); Khan and the team had used separate Methanolic and hexane extracts of leaves and stems ( Khan et al, 2018 ); Azizah and the team had used ethanolic and aqueous extracts of aerial parts ( Azizah et al, 2015 ); Muniandy and the team had used 90% hydroethanolic extract of stem ( Muniandy et al, 2018b ); Othman and the team had used ethanolic and aqueous extracts of aerial parts ( Othman et al, 2016 ); Tiwari and the team had used juice ( Tiwari et al, 2013 ); Rajamurugan and the team had used ethanolic extract of leaves ( Rajamurugan et al, 2013 ); Jain and the team had used methanolic extract of leaves ( Jain et al, 2016 ); Suganya and the team had used aqueous extract of leaves and stems ( Suganya et al, 2019 ); Mohd Hazli and the team had used hexane, ethyl acetate, ethanolic, and aqueous extracts of leaves and stem ( Mohd Hazli et al, 2019 ); Niraimathi and the team had used silver nanoparticles from aqueous extract of leaves ( Niraimathi et al, 2013 ); Yap and the team had used 100% ethanolic, 70% ethanolic, 80% methanolic, ethyl acetate, and aqueous extracts of the whole plant ( Yap et al, 2019 ); Kota and the team had used petroleum ether, ethyl acetate, chloroform, and methanolic extract of leaves ( Kota et al, 2017 ); Sundar and the team had used petroleum ether and methanolic extracts of leaves ( Sundar et al, 2019 ); Pathak and the team had used n-hexane and methanolic extracts of aerial parts ( Pathak et al, 2020 ); Khan and the team had used the volatile oil of leaves and flowers ( Khan et al, 2016 ); while Salvador and the team had used ethanolic extract and its four fractions; Acacetin 8-c-[ α -L-rhamnopyranoyl-(1→2)- β -D-glucopyranoside]; 2″- O -α-L-rhamnopyranosyl-vitexin; 2″- O - β -D-glucopyranosyl vitexin and Vitexin ( Salvador et al, 2006 ). Results from these researches left no doubt in the credibility and applicability of Alternanthera sessilis (L.) R.Br.…”