Seasonal variation of alkaloids of Adhatoda vasica and detection of glycosides and N-Oxides of vasicine and vasicinone

The distribution pattern of the alkaloids of A. Vasica has been studied with change of season. The study also resulted in the detection of glycosides and N-oxides of vasicine and vasicinone.     

Anti-ulcer activity of Adhatoda vasica Nees

Adhatoda vasica Nees (Acantheceae), commonly known as Vasaka, is a well-known plant in indigenous systems of medicine and is used for its beneficial effects, particularly in bronchitis. The present investigation was carried out to study the anti-ulcer activity of Adhatoda vasica leaves using two ulcer models (1) Ethanol-induced, and (2) Pylorus ligation plus aspirin-induced models. Adhatoda vasica leaf powder showeda considerable degree of anti-ulcer activity in experimental rats when compared with a control. The highest degree of activity (80%) was observed in the ethanol-induced ulceration model. Results of the study suggest that in addition to its classically established pharmacological activities, the plant also has immense potential as an anti-ulcer agent of great therapeutic relevance.     

Quantitative determination of vasicine and vasicinone in Adhatoda vasica by high performance capillary electrophoresis

A new method of capillary electrophoresis was developed for the quantitative determination of vasicine and vasicinone from Adhatoda vasica (L.) Nees. The electrophoretic separation was performed using a 47 cm x 50 microm ID (38.5 cm effective length) fused silica capillary. The samples were injected by pressure for 3 s at 50 mbar and the running voltage was 19 kV at the injector end of the capillary. The capillary temperature was maintained at 40 degrees C. The separation of the two alkaloids has been achieved within 11 min with good repeatability. The method was validated in terms of reproducibility, linearity, accuracy and applied for the quantitative determination of vasicine and vasicinone in A. vasica plant samples/extracts. Parameters affecting the resolution such as pH, temperature, organic modifier, buffer concentration and capillary dimensions were reported.     

New Pyrrolizidine Alkaloids and Glycosides from Anchusa strigosa

Six new pyrrolizidine alkaloids, a new carboxylic acid, a new phenolic and a new oleanane glycoside, together with the known compounds 7,7'-bis-(4-hydroxy-3,5-dimethoxyphenyl)-8,8'-dihydroxymethyltetrahydrofuran 4'-O-beta-D-glucopyranoside, rosmarinic acid, caffeic acid, tormentic acid 28-O-beta- D-glucopyranoside, euscaphic acid 28-O-beta-D-glucopyranoside, euscaphic acid, and allantoin were isolated from Anchusa strigosa roots. Their structures were established by high resolution NMR, MS, elemental analysis, and chemical reactions.     

Characterization and Lifetime Dietary Risk Assessment of Eighteen Pyrrolizidine Alkaloids and Pyrrolizidine Alkaloid N-Oxides in New Zealand Honey

Pyrrolizidine alkaloids (PAs) are a large group of botanical toxins of concern, as they are considered genotoxic carcinogens, with long-term dietary exposure presenting an elevated risk of liver cancer. PAs can contaminate honey through honeybees visiting the flowers of PA-containing plant species. A program of monitoring New Zealand honey has been undertaken over several years to build a comprehensive dataset on the concentration, regional and seasonal distribution, and botanical origin of 18 PAs and PA N-oxides. A bespoke probabilistic exposure model has then been used to assess the averaged lifetime dietary risk to honey consumers, with exposures at each percentile of the model characterized for risk using a margin of exposure from the Joint World Health Organization and United Nations Food and Agriculture Organization Expert Committee on Food Additives (JECFA) Benchmark Dose. Survey findings identify the typical PA types for New Zealand honey as lycopsamine, echimidine, retrorsine and senecionine. Regional and seasonal variation is evident in the types and levels of total PAs, linked to the ranges and flowering times of certain plants. Over a lifetime basis, the average exposure an individual will receive through honey consumption is considered within tolerable levels, although there are uncertainties over high and brand-loyal consumers, and other dietary contributors. An average lifetime risk to the general population from PAs in honey is not expected. However, given the uncertainties in the assessment, risk management approaches to limit or reduce exposures through honey are still of value.     

Alkaloids of Annonaceae. XXIX. Alkaloids of Annona muricata

From leaves, root - and stem - barks of Annona muricata L., seven isoquinoline alkaloids have been isolated: reticuline (main alkaloid), coclaurine, coreximine, atherosperminine, stepharine. Anomurine and anomuricine, two minor alkaloids, are new tetrahydrobenzylisoquinolines, with 5, 6, 7 substituted ring A. The phytochemical significance of these alkaloids is discussed.     

紫花地丁在不同季节总黄酮含量的变化

建立了UV法测定紫花地丁中总黄酮的含量,检测波长为510nm,平均回收率为99.8%.试验结果经方差分析显示,不同季节采收的紫花地丁中总黄酮含量有显著性差异.     

Alkaloids of Annonaceae. XXIX. Alkaloids of Annona muricata.]

From leaves, root - and stem - barks of ANNONA MURICATA L., seven isoquinoline alkaloids have been isolated: reticuline (main alkaloid), coclaurine, coreximine, atherosperminine, stepharine. Anomurine and anomuricine, two minor alkaloids, are new tetrahydrobenzylisoquinolines, with 5, 6, 7 substituted ring A. The phytochemical significance of these alkaloids is discussed.     

Synthesis and Structure-Activity Relationships of Vasicine Analogues as Bronchodilatory Agents

The series of vasicine (1) analogues, an alkaloid from Adhatoda vasica Nees., were synthesized with changes in A, B or C rings. Compounds 13-19 were evaluated for in vitro bronchodilatory activity using isolated guinea pig tracheal chain. Compounds 3-8 were also synthesized in good yields using microwave-mediated synthesis under solvent free conditions. Compounds 5 and 8 with seven-member C ring were more active than etofylline and caused 100% relaxation of both the histamine and acetycholine pre-contracted guinea pig tracheal chain. The structure-activity relationship studies showed that the quinazoline and oxo functionalities were essential for activity. The compounds without C ring and instead having aliphatic and phenyl substitutions in B ring showed relaxation against histamine pre-contracted tracheal chain only, 2-methyl substituted analogues, 12 and 13, being most active with 100% relaxation effect.     

Anticholinesterase activity of compounds related to geneserine tautomers. N-Oxides and 1,2-oxazines

A series of phenylcarbamate analogues of geneserine (8, 10, 12, 14) were synthesized from their counterparts, the phenylcarbamate analogues of physostigmine (2-5), by oxidation. The geneserine analogues can undergo tautomerism between N-oxide and 1,2-oxazine structures in a pH- and time-dependent manner. Assessment by (1)H NMR indicated that the N-oxide structure is adopted at neutral pH and that the compound exists in an equilibrium between several epimers. Evaluation of their biological action to inhibit human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), ex vivo, demonstrated that the N-oxide (7, 9, 11, 13, 15) and 1,2-oxazine (6, 8, 10, 12, 14) structures possessed similar potencies against AChE, but the latter structures were more potent against BChE. With the exception of the BChE selective inhibitor, 12, none of the geneserine analogues were as potent or enzyme subtype selective as their physostigmine analogue counterparts.     

Seasonal Variation of Essential Oil Yield and Composition of Thymus hyemalis

The aerial parts of THYMUS HYEMALIS Lange were collected throughout its complete vegetative cycle (April 1981 to March 1982) from the same locality. The yield and composition of essential oil have been determined in eleven samples with special reference to the content of 1,8-cineole, camphor, thymol, and carvacrol. It was found that the yield and composition of the oil changed from month to month. On the basis of the results obtained, July might be proposed as the most suitable month for harvesting T. HYEMALIS, giving the maximum yield in essential oil, which is especially rich in terpenic hydrocarbons at this time. Maximum levels of 1,8-cineole in August, however, might warrent harvesting during this month as well.