PHARMACOLOGICAL ASSESSMENT OF Lupinus arboreus Sims

PHARMACOLOGICAL ASSESSMENT OF Lupinus arboreus Sims (FABACEAE) METHANOL EXTRACT AND THREE ACTIVE CONSTITUENTS FOR ANTINOCICEPTIVE AND ANTI-INFLAMMATORY EFFECTS

ABSTRACT

The antinociceptive and anti-inflammatory properties of Lupinus arboreus leaf methanol extract and chemical constituents were examined. The research was conducted using an experimental design.

The extract was partitioned to produce fractions of hexane, ethylacetate, and methanol.

The extract and fractions were subjected to phytochemical testing. On crude methanol leaf extract (CME), an acute toxicity test (LD50) was performed. Bioactivity guided fractionation was performed on extract hexane fraction (HEF), ethylacetate fraction (EAF), and methanol fraction (MEF) using mice tail immersion, hot plate, acetic acid-induced tests, and formaldehyde- and egg albumin-induced rat paw oedema as activity guides for antinociceptive and anti-inflammatory studies, respectively. Bioactivity-guided silica gel column chromatography eluted with gradient mixtures was used to isolate the active ingredients. Phytochemical analysis, m.p. determination, UV, IR, NMR, and GC/MS spectral analyses were used to describe the extracted active components.

The crude methanol extract had an intraperitoneal (i.p) LD50 of 84.85 mg/kg. The presence of steroids, flavonoids, glycosides, terpenes, and saponins in the methanol extract was revealed by phytochemical analysis. Tannin, resin, reducing sugar, and protein were all present in moderate amounts.

Steroids and terpenes were found in the hexane fraction, whereas flavonoids and glycosides were found in the ethylacetate fraction. The hexane fraction yielded two active chemicals, AHF1 and AHF2, while the ethyl acetate fraction yielded AEF1. Steroids were present in the AHF1. AHF2 included terpenes, whereas AEF1 contained flavonoids. The crude methanol extract (CME) (30 and 60 mg/kg,) i.p produced dose-related resistance to heat pain as well as significant (p 0.01) pain inhibition. CME demonstrated dose-related antinociceptive action with 71.13 and 47.80% at 60 and 30 mg/kg, respectively, in an acetic-induced writhing test. HEF and EAF showed substantial (p 0.05) pain inhibition of 73 and 64%, respectively, whereas MEF caused just 24 percent pain inhibition. At 30 mg/kg, AHF1 and AHF2 fractionated from HEF inhibited pain by 75 and 71%, respectively (p 0.05). AEF1 (30 mg/kg) also decreased the pain reflex by 71% (p 0.05). At the fourth hour of egg albumin-induced (acute) oedema in rats, CME (30 and 60 mg/kg) inhibited oedema by 81.10 and 91.50%, respectively.

Similarly, at 60 mg/kg, hexane fraction (HEF) and ethylacetate (EAF) inhibited oedema by 79 and 40%, respectively, at the 4th hour. Methanol fraction (MEF) (60 mg/kg) had no significant effect (p> 0.05). The suppression of oedema by HEF and EAF was greater than that of aspirin (100 mg/kg). CME (30 and 60 mg/kg) significantly decreased formaldehyde-induced arthritis during a 4-hour period (p 0.05) (68 and 69% inhibition, respectively). Both HEF and EAF at 60 mg/kg i.p decreased the oedematous response to formaldehyde-induced arthritis considerably (p 0.05), producing 85.7 and 64.2% inhibition, respectively. The inhibitory effects of the isolates AHF1, AHF2, and AEF1 on egg albumin-induced (acute) oedema in rats were considerable and superior to that of aspirin (100 mg/kg) (46%). AHF1, AHF2, and AEF1 (30 mg/kg i.p) reduced formaldehyde-induced (chronic) oedema in rats by 79%, 72%, and 65%, respectively. Stigmastene 3, 6-dione (AHF1), ursolic acid (AHF 2), tetrahydroxyflavone-3a-rhamnoside (AEF1), and ellagic acid (AEF 2) were found as the separated active components. In this work, the extract and fractions of L. arboreus leaves displayed antinociceptive effects in several pain models, as well as anti-inflammatory benefits in both acute and chronic inflammation models. Antinociceptive and anti-inflammatory actions appear to be mediated by the isolated chemicals AHF1, AHF2, and AEF 1. Concurrently isolated was the antimicrobially active compound AEF2, identified as ellagic acid. For the first time, these chemicals were isolated and described from L. arboreus.