Comparative Evaluation of Pharmacognostic Characteristics, Phytochemical Composition, and Antioxidant Potential of Cosmos sulphureus Cav. and Calendula officinalis L.: A Critical Narrative Review on Flower Colour and Quality Standardisation
DOI:
https://doi.org/10.61280/m6kvm371Keywords:
Cosmos sulphureus, Calendula officinalis, Pharmacognosy, Flower colour, Total Phenolic content, Total flavonoid content, DPPH radical scavenging, Phytochemical standardisation.Abstract
Background: Cosmos sulphureus Cav. and Calendula officinalis L. belong to the family Asteraceae and are characterised by conspicuous yellow-to-orange inflorescences and notable phytochemical and antioxidant properties. However, the extent to which flower colour predicts phenolic composition, flavonoid abundance, and radical-scavenging activity remains uncertain. Objectives: This critical narrative review examines the comparative pharmacognostic characteristics, major phytochemical constituents, and evidence concerning colour-associated variation in total phenolic content (TPC), total flavonoid content (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity.
Methods: Relevant botanical reviews, primary investigations, and analytical-method publications were examined through targeted literature searches of accessible scholarly resources.
Key Findings: Published research on C. sulphureus identifies chlorogenic acid, caffeic acid, rutin, and quercetin in investigated extracts alongside demonstrable antioxidant activity [4]. In C. officinalis, flavonoids, phenolic acids, carotenoids, and triterpenoid constituents contribute to a complex phytochemical profile [1,3]. A study of 20 C. officinalis cultivars reported total flavonoid contents ranging from 0.21% to 0.68%, without establishing a conclusive relationship between floret colour and flavonoid abundance [6]. Methodological discrepancies—including variations in plant material, extraction conditions, calibration standards, and assay procedures—severely restrict quantitative comparisons between published studies, and direct, standardised comparisons of colour-defined morphs remain insufficient for both species.
Conclusions: Future investigations must combine authenticated botanical material, instrumental colour assessment, pigment profiling, validated spectrophotometric assays, and chromatographic characterisation to establish reproducible relationships between floral pigmentation, phytochemical composition, and antioxidant potential.
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