A new abietene diterpene, kaempfolienol (5S,6S,7S,9S,10S,11R,13S-abiet-8(14)-enepenta-6,7,9,11,13-ol, 1), was isolated from a rhizome extract of Kaempferia angustifolia Rosc. along with the known compounds crotepoxide, boesenboxide, zeylenol, 2'-hydroxy-4,4',6'-trimethoxychalcone, (24S)-24-methyl-5α-lanosta-9(11),25-dien-3β-ol, β-sitosterol and β-sitosterol-3-O-β-D-glucopyranoside. The structures of all compounds were elucidated on the basis of mass spectroscopic and NMR data. Zeylenol (2), the major constituent of the plant, was derivatized into diacetate, triacetate and epoxide derivatives through standard organic reactions. The cytotoxic activity of compounds 1, 2 and the zeylenol derivatives was evaluated against the HL-60, MCF-7, HT-29 and HeLa cell lines.
The interaction of bioactive compounds from ethanolic extracts of selected marine algae samples, separated on chromatographic plates, with nitric/nitrous acid was investigated. The nature of bioactive compounds in the marine algae extracts was characterised using UV absorption spectra before and after reaction with diluted nitric acid, and from the characteristic colour reaction after derivatization with anisaldehyde. It was found that diterpenes from Dictyota dichotoma, an edible brown algae, and sterols from green algae Caulerpa brachypus, bind nitric oxide and may act as a nitric oxide carrier. Although the carotenoid fucoxanthin, found in all brown marine algae also binds nitric oxide, the bonds between nitrogen and the fucoxanthin molecule are much stronger. Further studies are required to evaluate the effects of diterpenes from Dictyota dichotoma and sterols from green algae Caulerpa brachypus to see if they have beneficial cardiovascular effects. The method reported here should prove useful in screening large numbers of algae species for compounds with cardiovascular activity.
Andrographis paniculata (Burm. F.) Nees. is considered as the herb of the future due to its precious chemical compounds, andrographolide (ANDRO), neoandrographolide (NAG) and 14-deoxyandrographolide (DAG). This study aims to profile the metabolites in young and mature leaf at six different harvest ages using 1HNMR-based metabolomics combined with multivariate data analysis. Principal component analysis (PCA) indicated noticeable and clear discrimination between young and mature leaves. A comparison of the leaves stage indicated that young leaves were separated from mature leaves due to its larger quantity of ANDRO, NAG, DAG, glucose and sucrose. These similar metabolites are also responsible for the PCA separation into five clusters representing the harvest age at 14, 16, 18, 20, 22 weeks of leaves extract. Loading plots revealed that most of the ANDRO and NAG signals were present when the plant reached at the pre-flowering stage or 18 weeks after sowing (WAS). As a conclusion, A. paniculata young leaves at pre-flowering harvest age were found to be richer in ANDRO, NAG and DAG compared to mature leaves while glucose and choline increased with harvest age. Therefore, young leaves of A. paniculata should be harvested at 18 WAS in order to produce superior quality plant extracts for further applications by the herbal, nutraceutical and pharmaceutical industries.
Vitex agnus-castus L. (Lamiaceae) is a medicinal plant historically used throughout the Mediterranean region to treat menstrual cycle disorders, and is still used today as a clinically effective treatment for premenstrual syndrome. The pharmaceutical activity of the plant extract is linked to its ability to lower prolactin levels. This feature has been attributed to the presence of dopaminergic diterpenoids that can bind to dopamine receptors in the pituitary gland. Phytochemical analyses of V. agnus-castus show that it contains an enormous array of structurally related diterpenoids and, as such, holds potential as a rich source of new dopaminergic drugs. The present work investigated the localisation and biosynthesis of diterpenoids in V. agnus-castus. With the assistance of matrix-assisted laser desorption ionisation-mass spectrometry imaging (MALDI-MSI), diterpenoids were localised to trichomes on the surface of fruit and leaves. Analysis of a trichome-specific transcriptome database, coupled with expression studies, identified seven candidate genes involved in diterpenoid biosynthesis: three class II diterpene synthases (diTPSs); three class I diTPSs; and a cytochrome P450 (CYP). Combinatorial assays of the diTPSs resulted in the formation of a range of different diterpenes that can account for several of the backbones of bioactive diterpenoids observed in V. agnus-castus. The identified CYP, VacCYP76BK1, was found to catalyse 16-hydroxylation of the diol-diterpene, peregrinol, to labd-13Z-ene-9,15,16-triol when expressed in Saccharomyces cerevisiae. Notably, this product is a potential intermediate in the biosynthetic pathway towards bioactive furan- and lactone-containing diterpenoids that are present in this species.
Leaves of Andrographis paniculata and Orthosiphon stamineus were extracted with water, ethanol, methanol and chloroform to assess their potential as antibacterial and antioxidant agents. High performance liquid chromatography analysis showed that the methanolic extracts of A. paniculata and O. stamineus leaves gave the highest amounts of andrographolide and rosmarinic acid, respectively. These leaf extracts exhibited antimicrobial and antioxidant activities and, at the highest concentration tested (200 mg/mL), showed greater inhibitory effects against the Gram positive bacteria Bacillus cereus and Staphylococcus aureus than 10% acetic acid. Andrographis paniculata and O. stamineus methanolic and ethanolic leaf extracts also showed the strongest antioxidant activity as compared with the other extracts tested. The bioactive compounds present in these leaf extracts have the potential to be developed into natural antibacterial and antioxidant agents that may have applications in animal and human health.