Natural Products Journal, The - Volume 3, Issue 1, 2013

In continuation of our studies on the genus Salvia fourteen alcoholic extracts of Salvia species were evaluated for their anticholinesterase activity. Among them, the most active extract at 200 μg/mL was found to be S. staminea with the inhibition of 55.17 and 79.75% against enzymes AChE and BChE, respectively. Pure isolated compounds from S. staminea were investigated for anticholinesterase activity at 200 μM, and the abietane diterpenoids ferruginol and taxodione were found to be the most promising isolates, which were then further investigated at five different concentrations, and both diterpenoids exhibited high activity, particularly against BChE enzyme with IC50 values of 7.73 and 10.52 μM, respectively. Salvia chrysophylla and Salvia poculata extracts also exhibited moderate anticholinesterase activity.

A great number of research articles have been focused describing variation in the secondary metabolites of the organisms as chemotypes or chemovariation. However, the present definition and nomenclature of chemotype portray some problems such as: 1) low repeatability of natural product studies if a mixture of chemotypes is used in isolation studies; 2) risk of reporting chemotypes that do not exist due to similar variations encountered in seasonal and environmental differences, 3) reporting same chemotypes under different names. The problems addressed above demand an exact definition, a system of nomenclature and a systematic method to evaluate chemotypes. In order to solve these problems and to start a debate on the matter, an exact definition, a system of nomenclature and a systematic method to evaluate chemotypes were proposed. Addressing the above mentioned problems, chemotypes were defined as “organisms categorized under same species, subspecies or varieties having differences in quantity and quality of their component(s) in their whole chemical fingerprint that is related to genetic or genetic expression differences”. A trinominal additional name in parentheses after the binominal name of the organism was proposed for naming chemotypes. In this nomenclature, first name informs the initials of the author's name of the chemotype, second name describes the location of the chemotype and last name explains the frequency of distribution of chemotype in its location. For the identification of chemotypes, an approach that evaluates fingerprint analysis data of the extracts of the organism being obtained with solvents of different polarity together with the fingerprint analysis data of the essential oils (if the subject organism contains any essential oils) has been proposed.

Natural products from plants are an excellent source of Human pancreatic α-amylase (HPA) inhibitors which have therapeutic application as oral agents to control blood glucose levels. The mechanism of action by Bisdemethoxycurcumin (BDMC) has been reported, isolated from Curcuma longa rhizomes, which inactivates HPA, a target for type-2 diabetes. This study validates its mode of action and its target which has to date remained largely unknown. The cytotoxicity and bioactivity of crude extract and BDMC on the pancreatic acinar AR42J secretory model cell line were evaluated with LD50 value of 16.25 μg ml-1 and 63.53 μM, and secretory α-amylase inhibition of 41% and 30%, respectively. BDMC uncompetitively inhibits HPA (Ki' of 10.1μM) and a binding affinity (Ka) of 8.5 x 104 M-1 with the involvement of surface exposed aromatic residues. The thermodynamic parameters suggest that binding is both enthalpically and entropically driven with ΔGº of - 28.13 kJ mol-1. Computational ligand docking showed that inactivation depends on hydrogen bonding and π-π interactions. Thus, BDMC, a natural product could be lowering post-prandial glycemia via a novel mode of binding and inactivation of HPA and may proved to be a good drug candidate to reduce/control post-prandial hyperglycemia.

Since prehistoric times, herbs have been acclaimed for their efficacy to improve health, accelerate the healing process following injuries and the body's recovery from exercise. There exists a number of such well known curative and healing herbs like arnica, calendula, St. John's wort etc, which have been used for treating different kinds of sports injuries. This brief review comes up with an illustration of these promising herbs used as commonest remedies against different sports injuries.

Standardization is of great importance to ascertain the botanical identity and quality of herbal drugs. Among the various analytical tools available, HPLC is one of the major tools for the herbal drug standardization. Adhatoda vasica Nees is well known shrub described in Ayurveda particularly for the treatment of respiratory ailments. The potential of the plant as bronchodilator and antitussive is mainly attributed to the presence of pyrrolo [2,1-b] quinazoline alkaloids. In the present study, seasonal variation of the vasicine and deoxyvasicinone in roots and leaves of Adhatoda vasica has been investigated. Maximum amount of vasicine was found in the month of August in both leaves and roots whereas Deoxyvasicinone was found to be maximum in month of December- January in roots and in November for leaves. Vasicine and Deoxyvasicinone were present in higher amounts in leaves as compared to roots. The quantitative estimation of the alkaloids was done by HPLC.

On-line HPLC-NMR chemical profiling of crude extracts derived from the bulbs of the Australian carnivorous plant Drosera erythrohiza subspecies magna was undertaken. A combination of on-flow and stop-flow HPLC-NMR methodologies enabled partial identification of two structurally related naphthoquinones as well as a mixture of their corresponding glycosides. Subsequent semi-preparative HPLC off-line isolation followed by NMR spectroscopic and mass spectrometric analysis of crude extracts of the bulbs of the plant permitted the unequivocal identification of droserone, hydroxydroserone, droserone-5-O-β-glycoside and hydroxydroserone-5-O-β-glycoside. In addition off-line separation methodologies of the aerial parts of the plant led to the identification of the bioactive compound plumbagin. This study represents only the second application of HPLC-NMR to chemically profile crude extracts of an Australian plant.

Nasopharyngeal carcinoma (NPC), prevalent in Southeast Asia and Southern China, is a cancer that develops from the epithelium of the nasopharynx. Current treatments of NPC patients produce undesirable complications. There is growing interest in natural products with anti-proliferative potential to circumvent toxicity associated with synthetic anticancer drugs and radiation. This study evaluated the anti-proliferative activity of standardized methanol extract of Coscinium fenestratum and its major constituent, berberine against two cell lines used as a cell model for NPC. Using HPLC analysis, the content of berberine in the methanol extract of C. fenestratum stem was standardized to be 4.0 % w/w. C. fenestratum standardized methanol extract and berberine inhibited NPC cell proliferation in a concentration- and timedependent manner, determined using the MTS assay. NPC cells were relatively more sensitive than untransformed human skin keratinocyte when treated with both test substances. Cisplatin, a conventional drug, did not show this selectivity, killing the untransformed cells first before the NPC cells. Berberine displayed higher activity, suggesting the possibility that it is the bioactive component. Cell proliferation inhibition was verified by the decrease in Ki67 and PCNA proliferation markers. Growth kinetics was monitored dynamically using an impedance-based system. Flow cytometry analysis revealed that the inhibitory effect of berberine on cell cycle progression was through the arrest of the G1 phase. Morphological changes of NPC cell lines were observed microscopically. The morphological observation and altered growth kinetics were consistent with the cell proliferation and cell cycle progression experiments. This work showed the anti-proliferative properties of berberine, thus its potential use in the formula of natural remedies for the treatment of NPC.

Ethnopharmacological relevance: In the traditional system of medicine, the plant Capparis decidua is well known for curing a variety of ailments such as toothache, cough, asthma, intermittent fever, rheumatism and inflammation. Aim of the study: The aim of the current study was to isolate and characterize the constituent responsible for the antimicrobial activity of the ethanolic extract of C decidua. Materials and methods: The isolated compound was extracted from ethanolic extract & characterized by spectroscopic methods. The antimicrobial activity of isolated compound was carried out against gram positive strains (S aureus, M luteus, B subtilus) and gram negative ones (P aeruginosa, E coli), and Fungi like C albicans and A niger by the cup-plate assay method and minimum inhibitory concentrations (MICs). Results: The active principle Oleiyl glucoside (n-octadec-9-enyl- β-D- glucopyranoside) was isolated from the ethanolic extract. The MIC values of the compound against gram positive bacteria were 62.5μg/ml, 62.5 μg/ml, 125μg/ml and against gram negative ones 31.25μg/ml, 250μg/ml. The compound was found to be active against C albicans 250 μg/ml only. Conclusions: The isolated compound Oleiyl glucoside showed moderate activity against bacteria and fungi.

One new prenylated xanthone derivative, named adamaxanthone (1) and one new prenylated anthraquinone derivative, adamaquinone (2) were isolated, respectively, from the methanol extract of the fruits and the stem bark of Psorospermum adamauense along with nine known compounds, including two xanthones [1,4,5,7-tetrahydroxyxanthone (3) and 1,2,3-trimethoxyxanthone (4)], two anthraquinones [2-isoprenylemodin (5) and (vismiaquinone (6)], one ferruginin [kengaquinone (7)], two anthrones [kenganthranol A (8) and 3-geranyloxyemodinanthrone (9)], one bianthrone [bianthrone A2b (10)], and one flavonoid [catechin (11)]. The structures of the new compounds were elucidated using spectroscopic methods and by comparison of their spectral data with those of the previously known analogues. The isolated compounds were evaluated for their antimicrobial activity against a wide range of drug-resistant pathogens and compound (3) was revealed to be the most active.

Essential oil from aerial parts of Swertia cordata (G. Don.) Clarke obtained by steam distillation was analysed through Gas chromatography and Gas chromatography-mass spectrometry. The main compounds found were palmitic acid (8.34), caryophyllene oxide (5.65), pentadecanal (4.77) and lachnophyllum ester (4.14%). Different concentrations of essential oil were tested for antimicrobial activity by disc diffusion method. The oil was found active against gram positive bacteria and fungi.

The investigation was carried out to determine the chemical composition of the fatty acids methyl esters (FAME) and leaf of Nyctanthes arbortristis was analyzed by gas liquid chromatography (GLC). GLC analyses of methyl ester lead to identify twenty two and fifteen fatty acids in the leaf of pet-ether and hexane extracts mixture (PH) and chloroform extract (CL), respectively. A Majority fatty acids, like palmitic acid (C16:0, 25.46%), arachidic acid (C20:0, 24.82%) and oleic acid (C18:1, 8.84%) were identified in leaf PH. Chloroform extract of FAME contains palmitic acid (C16:0, 23.9%), alfa-linolenic acid (C18:3, 15.11%) and oleic acid (C18:1, 14.98%) as major fatty acids in leaf. In this study, a new extraction method has been established.

Aim of the study: This work was targeted to investigate the cytotoxic and antioxidant constituents of Euphorbia orthoclada leaves, traditionally used for treating kidney stones, abscesses, osteomyelitis, dysentery, and asthma as well as bacillary and other infectious diseases. Methods: E. orthoclada leaves were extracted with methanol and the methanol phase was partitioned between cyclohexane. The ethyl acetate soluble fraction of the methanol extract was successively separated on silica gel and Sephadex LH-20 and the fractions were analysed by HPLC-UV-ESIMS and screened for cytotoxicity and antioxidant properties. The isolated compounds were elucidated by diverse spectroscopic and spectrometric methods.The cytotoxicity of fractions and pure compounds was evaluated using brine shrimp larvae (Artemia salina), while the antioxidant activity was determined by the DPPH radical-scavenging method. Results: Both cyclohexane and ethyl acetate fractions were toxic against brine shrimp larvae (Artemia salina) at a concentration of 10 μg/mL with mortality rates of 62% and 70%, respectively; however, the ethyl acetate extract proved to have the most effective antioxidant activity with an EC50 value of 3.45 ± 0.01 μg/mL. Five phenolic compounds 1-5 were isolated from the EtOAc extract by successive chromatographic procedures (silica gel, Sephadex LH-20). Among them, quercetin-3-O-α-D-arabinoside (2) (28.5 ± 0.11 μg/mL), kaempferol-3-O-β-D-glucoside (4) (37.2 ± 0.17 μg/mL), kaempferol-3-O-α-D-arabinoside (3) (38.4 ± 0.13 μg/mL) and gallic acid (1) (55.22 ± 0.15 μg/mL) displayed the highest antioxidant activity, while 3,3',4'-trimethylellagic acid 4-O-glucoside (5) (63.90 ± 0.09 μg/mL) was more toxic than the other constituents on brine shrimp larvae when tested at 10 μg/mL (mortality rate of 65 %). Conclusion: The medicinal plant Euphorbia orthoclada - namely its chemical constituents - has been investigated for the first time in this project. The cytotoxic and antioxidant properties of the pure secondary metabolites explain the use of this plant in traditional medicine. Moreover, the isolation of compounds 2, 3 and 4 from E. orthoclada emphasizes that these metabolites may be considered as chemotaxonomic markers of the genus Euphorbia.