Bioactivities of Plectranthus ecklonii Constituents

Abstract

Plectranthus ecklonii Benth. is traditionally used in South Africa for treating stomach aches, nausea, vomiting and meningitis. Bioassay-guided fractionation of the ethyl acetate extract of the plant led to the isolation of two known compounds, parvifloron D and parvifloron F, neither of which has been previously reported for this species. The compounds exhibited minimum inhibitory concentrations of 15.6 and 31.2 µg/mL, respectively against Listeria monocytogenes, whereas the values against a drug-sensitive strain of Mycobacterium tuberculosis were 190 and 95 µg/mL, respectively. The ethyl acetate extract of P. ecklonii and its isolated compounds were tested for their activity on tyrosinase inhibition. The concentration at which half the tyrosinase activity was inhibited (IC 50) by the extract was found to be 61.7 ± 2.7 µg/mL. The antibacterial activity of the extract and its isolated compounds correlates with the traditional use of the plant for various ailments such as stomach aches, diarrhea and skin diseases. The fifty percent inhibitory concentrations of parvifloron D and parvifloron F against vero cell lines were found to be 2.9 µg/mL and 1.6 µg/mL, respectively. This is the first report of the bioactivity of P. ecklonii extract and its constituents.

An easy and stereoselective rearrangement of an abietane diterpenoid into a bioactive microstegiol derivative

“…Parvifloron D (2), previously reported as an antibacterial metabolite from P. ecklonii (Nyila et al, 2009) smegmatis and C. albicans. Though microstegiol (1) has been reported (Kabouche et al, 2005;Ulubelen et al, 2000) as a weak microbial growth inhibitory compound, its derivative 3 revealed a higher activity against six of the Gram-positive strains tested, those that gave MIC values ranges from 3.91 to 7.81 mg/ml.…”

Assessment of the Potential Skin Application of Plectranthus ecklonii Benth.

“…On the other hand, the major abietane diterpenoid of P. ecklonii, parvifloron D (ParvD, previously isolated [7]) ( Figure 1b), presents antibacterial activity, which can be associated with the folk uses of the plant for treating gastrointestinal distress and skin diseases [8]. Additionally, antityrosinase activity [9] and cytotoxicity properties [7,10] have been reported for ParvD. To obtain the optimal benefits of topical formulations, the compounds that are applied over cutaneous tissue must reach their action sites to perform their biological activities.…”

“…On the other hand, cosmetic formulations are generally considered safer if the permeation of their main compounds is limited to the upper layers of the skin and does not reach the microcirculation. Thus, in the assessment of a potential candidate for topical administration, skin permeation assays are indispensable [8,9].…”

Insight the Biological Activities of Selected Abietane Diterpenes Isolated from Plectranthus spp.

“…However, the acetone extracts are rich in various royleanones, including 7β,6β-dihydroxyroyleanone (Diroy) and 7α-acetoxy-6β-hydroxyroyleanone (Roy) [18]. Another Plectranthus member, P. ecklonii, is highly rich in another abietane diterpene, parvifloron D (Parv D), which has long been known to display potent anticancer activities [19,20].To gain a greater insight into their potential use in cancer treatment, the present study examines the apoptotic character of these Plectranthus-derived abietanes and their activities against a human glioma cell line.…”