Abstract:
Background: Plectranthus species belonging to the family Lamiaceae are commonly used in
traditional medicine preparations. Plectranthus zeylanicus belonging to this family is
erroneously used in formulations due to the taxonomic ambiguity and morphological confusion
with other Plectranthus species including Plectranthus amboinicus. Though they are
morphologically similar, they have different therapeutic and pharmacological uses. Hence
inappropriate use of them can lead to undesirable adverse effects.
Objectives: To determine phytochemical, proximate and High Performance Thin Layer
Chromatographic (HPTLC) profiles for the preliminary identification of P. zeylanicus Benth
(Iriweriya) which is commonly used to treat respiratory, gastrointestinal, dermatological and
neurological disorders.
Methods: Mature whole aerial parts were obtained from western province, Sri Lanka,
authenticated from National Herbarium, Peradeniya and oven dried. Extracts were obtained with
methanol, acetone and distilled water as per WHO Guidelines. Preliminary phytochemical
screening, proximate analysis and HPTLC were conducted to each extract.
Results: Phytochemical screening revealed that alkaloids, terpenoids, triterpenes and
anthraquinones are present in all extracts while tannins, phenols, diterpenes and flavonoids are
present only in methanol and aqueous extracts. Saponins and carbohydrates were available only
in aqueous extract while proteins and glycosides were found only in acetone extract. Proximate
analysis revealed that total ash, acid insoluble ash, water soluble ash, loss on drying,
extractability in methanol, acetone and water were 16.12±0.91%, 0.64±0.02%, 7.19±1.27%,
17.09±0.14%, 16.82±0.23%, 5.13±0.13% and 60.27±1.72% w/w, respectively. Normal phase
HPTLC fingerprint of methanol extract showed 11 peaks with methanol: distilled water: acetic
acid (2:5:3) while acetone extract showed 10 peaks for distilled water: methanol: acetone
(4:2:4). Reverse phase HPTLC fingerprint of aqueous extract showed 9 peaks with methanol:
distilled water (7:3). Each was done in triplicate and results were expressed as mean ± standard
deviation.
Conclusions: Therefore, the above parameters can be used as preliminary tools for
identification and authentication of P. zeylanicus as raw materials in Ayurveda manufacturing
