ABSTRACT

The Phytochemical evaluation of the secondary metabolites in Justicia spicigera using n-hexane, methanol, chloroform and ethanol extracts revealed the bioavailability of bioactive compounds comprising alkaloids (3.048 - 8.265 mg/100 g), tannins (0.080-0.254 mg/100 g), phenols (0.014 - 0.029 mg/100 g), saponins (0.564-0.744 mg/100 g), flavonoids (0.780-9.820 mg/100 g) and steroids (0.667-1.277 mg/100 g). Minerals content revealed the presence of magnesium (1.094 -1.277 mg/100 g), calcium (3.707-4.509 mg/100 g), potassium (1.2-1.3 mg/100 g), sodium (0.325 - 0.55 mg/100 g), phosphorous (0.689-0.708 mg/100 g)., manganese (5.80-7.98 mg/100 g) and the Trace element analysis revealed - zinc (11.13-15.10 mg/100 g), copper (4.88-4.98 mg/100 g), iron (51.30-53.08 mg/100 g) and lead (1.60-2.46 mg/100 g). The vitamins content was ascorbic acid (92.40-57.20 mg/100 g), β-carotenoid (312.50-474.54 mg/100 g), riboflavin (2.63-4.13 mg/100 g), thiamin (0.38-0.75 mg/100 g) and niacin (0.84-1.41 mg/100 g). Extracts of Justicia spicigera prepared with solvents of different polarities (n-Hexane, Chloroform, Methanol, and Ethanol) were used to analyze the anti-bacterial properties using the test microorganisms Streptococcus pneumonia, Salmonella typhi, Escherichia coli and Aspergilus niger with the positive control as Ciprofloxacin. Minimum inhibitory concentration (MIC) was attained at 125-250 mg/ml for E.coli, S. typhi, and S. pneumonia and (MIC) was attained at 250-500 mg/ml for Aspergilus niger. Chemical investigation of the leaves of a herbaceous medicinal plant Justicia spicigera resulted in the isolation of two natural products – Compound S₁₈ and Compound S₂₁ from the crude methanol extract of the leaves. Isolation of Compound S₁₈ and Compound S₂₁ was carried out by Column Chromatography using silica gel as the adsorbent. The composition of the crude mixture was examined using thin layer chromatography. The combined Infra-red, Proton and DEPT Nuclear Magnetic Resonances, Mass Spectroscopy, ¹H-¹H COSY and ¹H-¹³C-HMBC were used as spectral techniques to propose the structures of the compounds. The High Resolution Electro-Spray Impact Mass Spectroscopy analysis of Compound S₁₈ showed a molecular ion (M+) peak at m/z C₃₅H₅₈O₈ and Compound S₂₁ of molecular ion (M+) peak at m/z C₃₁H₄₇O₁₆. The characterization of the isolated natural products from Justicia spicigera revealed Compound S₁₈ is a triterpenoidal glycoside and Compound S₂₁ is confirmed to be a δ-lactone glycoside. The presence of bioactive natural products may be a contributor to the antimicrobial, antioxidant, anti-inflammatory, liver protector, analgesic, anti-cancer, anti-diabetic and antacid properties exhibited by Justicia spicigera. Justicia spicigera offers a wide scope for pharmaceutical industries to use in drug formulations.