Analgesic and anti-inflammatory potential of Lupeol isolated from Indian traditional medicinal plant Crateva adansonii screened through in vivo and in silico approaches.

Background: Lupeol, a triterpene bioactive compound isolated from Indian traditional plant Crateva adansonii acted as promising and alternative anti-inflammatory agent to treatments of diseases related to inflammation. The inflammatory process in the body serves an important function in the control and repair of injury. However, it is self-perpetuating in number of disease conditions, which must be prevented and treated. Worldwide most prescribing NASID drug shows severe side effects. Whereas drug from natural origin shows dual inhibition of inflammatory and analgesic target protein with more efficacy and less side effects than NSAID drugs. Our study aims to isolate and screen the analgesic and anti-inflammatory potential of lupeol, a pentacyclic triterpenoid isolated from leaf extract of Crateva adansonii belongs to Capparaceae family commonly used Indian traditional medicine for treating inflammatory diseases.

Results: Methanol and chloroform leaf extracts (ME and CE) and lupeol fraction (LF) of plant Crateva adansonii is investigated through employing in vivo male Wistar albino rat model. Acute toxicity study of C. adansonii ME and CE leaf extracts reveals that no mortality and no behavioral changes in experimental animals up to 2 g/kg. So no lethal dose we consider two optimal doses 200 and 400 mg of plant leaf extracts for in vivo inflammatory and analgesic study. In vivo acute and chronic anti-inflammatory activity was carried out through carrageenan-induced rat paw edema and cotton pellet-induced granuloma models. LF (100 mg/kg, oral route) of Crateva adansonii evoked highest percentage of inflammation inhibition (50 and 33.96% respectively) in both in vivo acute and chronic inflammation model among all tested samples (ME and CE 200 mg and 400 mg/kg, oral route) including reference standard (10 mg/kg, oral route) indomethacin. Carrageenan-challenged experimental animals were screened for one inflammatory marker enzyme myeloperoxidase (MPO), inflammatory products such as Prostaglandrin E₂ (PGE₂), and eight different cytokines markers (TNFα, IL-6, IFN γ, IL-1α, IL-1β, MCP-1, Rantes, and MIP) associated with inflammation reveals that LF (100 mg/kg, oral route) of Crateva adansonii shows prominent anti-inflammatory activity than reference standard indomethacin (10 mg/kg, oral route) over all these biological tested parameters. In vivo analgesic assays such as hot plate assay and acetic acid-induced writhing assay revealed that LF (100 mg/kg, oral route) possesses significant analgesic activity (11.60 s and 69.05%) when compared with standard drug pentazocine(10 mg/kg, oral route). Finally, we made an in silico screening of lupeol against analgesic (nAChR) and anti-inflammatory (COX-2) target proteins reveals that lupeol possess highest binding affinity with nAChR and COX-2 target proteins (- 8.5 and - 9.0 Kcal/mol) over the reference standard pentazocine and indomethacin (- 7.0 and - 8.4 Kcal/mol) respectively.

Conclusion: The present study result provides a pharmacological evidences for analgesic and anti-inflammatory potential of lupeol isolated from Indian traditional plant Crateva adansonii act as a multi-target agent with immense anti-inflammatory potential targeting key molecules of inflammation such as MPO, PGE₂, and eight pro-inflammatory cytokine markers. Outcome of present study is to find promising anti-inflammatory bioactive agents from the cheapest Indian traditional medicinal plant sources useful for pharmaceutical industries.