Phenolic content of Ruprechtia salicifolia leaf and its immunomodulatory, anti-inflammatory, anticancer and antibacterial activity

Objectives

This work aimed to isolate phenolics from leaves of Ruprechtia salicifolia and evaluate its immunomodulatory, anti-inflammatory, anticancer and antibacterial activity.

Methods

80% MeOH leaf extract was subjected to chromatographic separation, structures of the isolated compounds were established by different chromatographic and spectral techniques UV, MS, ¹H and ¹³C NMR. Immunomodulatory was evaluated through RAW 264.7 macrophages proliferation by MTT assay. Anti-inflammatory was evaluated by inhibition of NO and TNF-α factor generation in LPS-stimulated cells through bicinchoninici acid assay and ELISA assay, respectively. Cytotoxicity estimated through Hep-G2, MCF-7 and HCT-116 cell lines measured by MTT assay. Antibacterial activity tested by agar diffusion method.

Results

Eleven known phenolic compounds were isolated for the first time from this species including five flavonoid glycosides viz; Rutin 3, quercetin 3-O-arabinoglucoside 4, apigenin 7-O-β-d-glucoside 5, quercetin 3-O-α-l-arabinofuranoside 6 and isoquercetin 7 along with four aglycones viz; kaemferide 8, apigenin 9, quercetin 10 and naringenin 11 and two phenolic acids; caffeic 1 and gallic 2. Compounds 5 showed the most activity increasing macrophage proliferation implying immunomodulatory activity. 80% MeOH extract, 4, 5 and 11 inhibited nitrite oxide by 68.19%, 52.95%, 20.33% and 15.22%, respectively and TNF-α generation by 70.82%, 29.88%, 13.13% and 6.14%, respectively in LPS-stimulated cells implying anti-inflammatory activity. 80% MeOH leaf extract and the tested compounds 4 and 5 were safe possessing no cytotoxic activity against hepatocellular carcinoma (Hep-G2), breast adenocarcinoma (MCF-7) and colon carcinoma (HCT-116), while Compound 11 had cytotoxicity against only HCT-116 cells (IC₅₀ = 27.67 μg/ml). Also 80% MeOH leaf extract showed antibacterial activity against both G +ve and G −ve bacteria, moreover it inhibits growth of Klebsiella pneumonia strain, which is resistant to Ciprofloxacin broad-spectrum antibiotic.

Conclusions

R. salicifolia contain phenolics of immunomodulatory anti-inflammatory, cytotoxicity and antibacterial activity, giving R. salicifolia grate potential as a medicinal natural drug.