Chemometric-enhanced metabolic profiling of different plant parts belonging to two Bougainvillea species using UPLC-MS/MS spectrometry: Correlation to in vitro anti-inflammatory activity

Abstract

Bougainvillea is considered as an important source of environment-friendly safe pigmenting agents, namely anthocyanins that are widely used in food, textile, cosmetic, and pharmaceutical industries. This study aimed to investigate the resemblance and variation in the chemical profiles of B. spectabilis Willd and B. glabra Choisy flowers and leaves extracts utilizing UPLC-MS/MS analysis in combination with chemometric tools. Forty-four compounds were tentatively annotated in the tested Bougainvillea extracts. Flavonoids, anthocyanins, mono, di, and triterpenes in addition to phenolic acids were the major classes of the annotated compounds. B. spectabilis flowers samples showed significant variations in their chemical profiles compared to the other tested extracts. The downregulating effect of the tested extracts on the expression of four pro-inflammatory markers (TNF-α, IL-6, IL-1β, and INF-γ) genes was assessed using real-time-PCR technique. All tested extracts abolished pro-inflammatory genes upregulation to levels comparable to those exhibited by piroxicam, on top of which were B. spectabilis leaves that exhibited the strongest anti-inflammatory activity due to their enrichment of bioactive metabolites that significantly influenced the expression of the proinflammatory biomarkers. Orthogonal projection to latent structure-discriminant analysis (OPLS) and coefficient plots unveiled the biomarkers contributing to the anti-inflammatory efficacy including Caffeic acid hexoside, p-hydroxybenzoic acid, sinapinic acid, quercetin 3-O-(4-caffeoylrhamnosyl-rhamnosyl-hexoside), rutin, neoeriocitrin, luteolin robinobioside, quercetin glucuronide (miquelianin) that seemed to be profoundly dominant in B.spectabilis leaves samples. This study showed that Bougainvillea plants can serve as important sources of valuable anti-inflammatory compounds besides their pronounced industrial applications.