#116 GC-MS fingerprinting and in-vitro biological evaluation of hydroalcoholic extract of Rosemary officinalis Linn. leaves

Abstract

Rosmarinus officinalis Linn. is an aromatic perennial herb with fragrant evergreen needle-like leaves. It is member species of the Lamiaceae family. It is used commercially for antispasmodic, antimicrobial, anti-inflammatory, analgesic, antipyretic, cardiac tonic, antioxidant, antiapoptotic, anti-tumorigenic, antinociceptive, antiasthmatic, and neuroprotective properties. Our study focuses on GC-MS phytochemical analysis and biological evaluation of hydroalcoholic extract of Rosemary officinalis along with its bioassay-guided fractions viz. n-hexane and chloroform through in-vitro anti-inflammatory and antimicrobial activity. Using the solvent, hydroalcoholic extracted the Rosemary leaves via triple kinetic maceration process. Then, the obtained mother tincture of the hydroalcoholic extract was subjected to bioassay-guided fractionation using various polar and non-polar solvents such as chloroform and n-hexane. Hydroalcoholic extract's phytochemical nature and its two fractions from Rosemary officinalis were confirmed by its spectral and chromatography analysis through UV-Vis and GC-MS. Hydroalcoholic extract and its two fractions of Rosemary leaves were evaluated for their in-vitro anti inflammatory and antibacterial activities by using various doses of 150, 250, 350 mg/kg against gram-positive (Staphylococcus aureus, Bacillus subtilis and Pseudomonas aureus) and gram-negative (Klebsiella pneumonia, Escherichia coli, and Proteus vulgaris) bacteria by agar plate diffusion method. Our study results revealed that the phytochemical screening through UV-Vis and GC-MSanalysis of hydroalcoholic extract of Rosemary leaves showed the presence of flavonoids, alkaloids, tannins, sterols, terpenes, and saponins. Further, the hydroalcoholic (HA), chloroform (CH), and n-hexane (NH) extract on in-vitro anti-inflammatory activity showed noteworthy inhibition viz. HA: 28.77%, 51.69%, and 75.49%, CH: 32.54%, 55.32%, and 78.42%, NH: 25.68%, 49.51%, and 66.82% at various doses, respectively, which was compared with standard drug Indomethacin (10 mg/kg). In addition, in-vitro antimicrobial studies showed significant inhibition on both gram-positive and gram-negative bacteria at (CH:1000 µg/mL, HA: 500 µg/mL, NH: 250 µg/mL). Our present study revealed that the chloroform fraction of Rosemary officinalis Linn possesses good antimicrobial and anti inflammatory activities compared with the hydroalcoholic and n-hexane extracts. This promising result may be due to the rich flavonoid content in chloroform extract. However, further study is required to know the complete mechanism of these extracts on the inflammatory process and use these extracts for life-threatening problems like cancer and tuberculosis is under process.