Tulsi plant has medicinal values due to the presence of the following

Question

UnlockIAS · Accepted Answer

Correct — C, Phenols and Flavonoids. Tulsi (Ocimum tenuiflorum, syn. Ocimum sanctum; holy basil, family Lamiaceae) owes its medicinal reputation to its secondary metabolites, and the dominant group among them is polyphenolic. Eugenol — a phenolic compound (4-allyl-2-methoxyphenol) — is the principal constituent of tulsi leaf essential oil and carries much of its antimicrobial and anti-inflammatory activity; alongside it the leaves contain phenolic acids such as rosmarinic acid and a set of flavonoids. Phenolic compounds are powerful antioxidants because the hydrogen of the phenolic –OH group is readily donated to neutralise free radicals, and that is the biochemical basis of the plant's traditional use.

Why the other options are wrong — (a) Plants do not store mineral acids such as hydrochloric or sulphuric acid in their tissues, and no inorganic acid is responsible for tulsi's medicinal properties.  (b) Too general, and it misses the active chemistry. Tulsi does contain rosmarinic acid — but that is itself a phenolic acid, and its activity comes from the phenol group, not from being an ordinary organic acid. The chief constituent, eugenol, is a phenol and not an acid at all, while the everyday plant organic acids (citric, malic, oxalic) have no such medicinal role.  (d) Wrong, because a specific and well-documented class of compounds — the phenolics and flavonoids — is exactly what accounts for the plant's medicinal value.

Concept: Plants make primary metabolites (sugars, amino acids, lipids) that keep them alive, and secondary metabolites that they do not strictly need for growth — alkaloids, terpenoids, glycosides and phenolics/flavonoids. Almost every medicinal plant is medicinal because of its secondary metabolites. In tulsi that role falls to the polyphenols: eugenol and other phenylpropanoids in the essential oil, phenolic acids such as rosmarinic acid, and leaf flavonoids, which together give antioxidant, anti-inflammatory and antimicrobial activity.

State PCS 2019 Q19 — Science & Technology PYQ with Answer

State PCS 2019 Q19 — Science & Technology PYQ with Answer