POM analyses, immunomodulatory, cytotoxic activities and polyphenolic constituents of Callistemon viridiflorus fruits

Phytochemical study on 80% ethanolic extract of Callistemon viridiflorus Sims fruits (CVF) resulted in isolation of five phenolic compounds 1; Gallic acid, 2; Ellagic acid, 3; Reynoutrin, 4; Methoxy ellagic acid, 5; Quercetin. Petra/Osiris/Molinspiration (POM) analyses predicted that Reynoutrin and Quercetin have interesting potential activities, also Reynoutrin is found to be safer in relation to Quercetin. 80% ethanolic extract of CVF, Reynoutrin and Quercetin displayed remarkable immunomodulatory activity, as increased proliferation of RAW 264.7 macrophage cells by 1.48, 1.51 and 1.46 fold respectively. 80% ethanolic extract of the C. viridiflorus fruits showed significant cytotoxic activity against P388 leukemia cells (IC₅₀ = 15.11 µg/ml), followed by Quercetin (IC₅₀ = 21.5 µg/ml) then Reynoutrin (IC₅₀ = 33.32 µg/ml).