Wild Marigold Research Articles

Optimization of DNA extraction from seeds and fresh leaf tissues of wild marigold (Tagetes minuta) for polymerase chain reaction analysis

Tagetes, a genus of flowering marigolds in the family Asteraceae (Compositeae), is reported to be a medicinal plant with hypotensive, spasmolytic, anti-inflammatory, antimicrobial, and antifungal properties. Tagetes minuta characteristically contains high concentrations of essential oils, flavonoids, polyphenols, and polysaccharides that interfere with DNA, causing erroneous or no PCR products. We tested and modified various standard protocols in an effort to isolate high-quality DNA from different plant tissues of T. minuta. We used sun-dried, shade-dried and fresh-leaf tissues, as well as seeds for DNA analysis. The DNA obtained from seeds and fresh-leaf tissues with a modified cetyltrimethylammonium bromide buffer protocol was of good quality, with no colored pigments and contaminants. We were able to obtain good quality DNA from fresh leaf tissues without using liquid nitrogen. A relatively large amount of DNA was also extracted from the sun- and shade-dried tissues, but its quality was not as good as that from seeds. The DNA extracted from seeds and fresh leaves was successfully amplified by PCR using arbitrary RAPD primers. The same protocol will probably be useful for extracting high-molecular weight DNA from other plant materials containing large amounts of secondary metabolites and essential oils.

Avaliação in vitro da atividade antifúngica de extratos de plantas e óleo de eucalipto sobre Trichophyton mentagrophytes

O presente estudo teve como objetivo determinar a ação antifúngica de extratos de plantas medicinais e óleo de eucalipto frente ao dermatófito Trichophyton mentagropytes, visando a utilização da fitoterapia no controle. As plantas utilizadas na obtenção dos extratos foram arruda (Ruta graveolens), citronela (Cymbopogon nardus), cravo de defunto (Tagetes minuta), eucalipto (Eucalyptus spp), graviola (Annona muricata), fruta do conde (Annona spp), manga (Mangifera indica), romã (Punica granatum), flores e folhas de primavera (Bougainvillea spectabilis). Verificou-se que uso de 0,5% óleo de eucalipto no combate ao T. mentagropytes foi eficaz, já os extratos de citronela (4%) eucalipto (5%) e romã (8%) atuaram como fungistáticos e os restantes não devem ser usados contra este dermatófito porque não causaram nenhum efeito.

Effect of planting date on growth, development, aerial biomass partitioning and essential oil productivity of wild marigold ( Tagetes minuta) in mid hills of Indian western Himalaya

A field investigation was conducted at the Institute of Himalayan Bioresource Technology, Palampur during the year 2005 to study the effect of planting dates on duration of growth and development in wild marigold ( Tagetes minuta). Duration of growth phases (vegetative phase to budding phase and budding phase to 50% flowering phase), aerial biomass partitioning and essential oil production were analysed. Plantings were done in seven consequent meteorological standard weeks (MSWs) starting from the 30th MSW (30 July–5 August). Planting time coincided with distinct changes in weather parameters and consequently significant variation in the performance of the crop. The results indicated that the crop planted in the 30th and 31st MSW had the longest duration of growth and highest aerial biomass. But it partitioned more biomass towards the stem, whereas the crop planted in the 35th MSW produced significantly less biomass than the former and partitioned more towards leaf and flower and had maximum essential oil content and production. The crop planted at the 36th MSW had the minimum field duration of growth of 50 days, but the partitioning towards leaf and flower were higher than the longest field duration of growth (30th MSW). The study clearly indicated that planting dates had profound influence on growth and development of T. minuta as reflected from the significant variation on growth phase duration, aerial biomass partitioning, herb and essential oil yield.

Variations in quantitative and qualitative characteristics of wild marigold ( Tagetes minuta L.) oils distilled under vacuum and at NTP

Essential oil of Tagetes minuta was distilled in vacuo in a mini distillation apparatus to study and compare the qualitative and quantitative characteristics vis-à-vis oil distilled by conventional distillation technique at normal temperature and pressure (NTP), which revealed that higher oil yield (1.56%) was obtained in the oil distilled by conventional distillation technique at NTP and decreased gradually with increase in vacuum to 150 mmHg (1.16%), 200 mmHg (1.07%) and 225 mmHg (0.91%). Concentration of monoterpene hydrocarbons (MH) was found maximum (55.3%) in the oil distilled at NTP and decreased with increase in vacuum to 150 mmHg (35.2%), 200 mmHg (31.4%) and 225 mmHg (27.5%). On the contrary, oxygenated monoterpenes (OM) were found minimum (22.9%) in the NTP distilled oil but increased with increase in vacuum to 150 mmHg (55.4%), 200 mmHg (61.3%) and 225 mmHg (65.3%). Sequential evolution of chemical compounds was also studied by distilling the oil at 225 mmHg vacuum and found that the lipophilic effect plays an important role in distillation of MHs. Due to the high concentration of these unsaturated MHs, the oil gets polymerized easily when exposed to unfavorable conditions and this can be minimized by reducing the concentration of these compounds by distilling the plant material under vacuum thus increasing the shelf life of the oil. The physicochemical properties of the oil were also evaluated. Vacuum distilled oil samples possessed better solubility in alcohol than NTP distilled oils. The olfactory evaluation of the samples revealed that the oil distilled at NTP possessed powerful, peculiar and disagreeable odour with burnt note, whereas the oils distilled in vacuo has pleasant odour varied from powerful fruity odour without any burning note to near true-to-nature odour of the flowers with increase in vacuum. Due to these improved characteristics, the in vacuo distilled oil of T. minuta is recommended for exploring its application in high grade perfumes, flavours and other formulations.

Techno-economic feasibility of wild marigold (Tagetes minuta) oil production in Himachal Pradesh

Essential oil production from Wild Marigold (Tagetes minuta L.) crop in selected locations of Himachal Pradesh has become a popular practice for gaining additional income and employment in farm sector. The study presents economics of essential oil production having components of cultivation and oil distillation in Himachal Pradesh, being practiced by the local farmers. Cost of cultivation for the average herbage yield of 200 qs was worked out to be Rs. 42,497/ha/crop season. Cost of oil production and net returns were determined as Rs. 1,175.28/kg oil and Rs. 41,236/ha/season, respectively. T. minuta oil production was not only techno-economically feasible but also a remunerative venture with a benefit-cost ratio (BCR) of 1.70, payback period of 4.24 years (8.48 seasons), break even production at 31 kg oil and rate of return on total capital at 15.78 % as found out from the study.

Antioxidant properties of marigold extracts

The influence of methanolic and water extracts of growing wild marigold, Calendula arvensis L. (GWM) and cultivated marigold, Calendula officinalis L. (CM), in a concentration range of 0.10–0.90 mg/ml, was evaluated on three different free-radical species: 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH), hydroxyl radical and lipid peroxyl radical using electron spin resonance (ESR) spectroscopy. These extracts of CM and GWM, scavenged all types of investigated radicals in dependence on their applied concentrations. Generally, CM extracts possessed better scavenging and antioxidant activity than GMW extracts, while methanolic extracts exhibited lower activities than water extracts. Water extracts of CM had the best antioxidant properties; 0.75 mg/ml extracts completely eliminated hydroxyl radical, which was generated in Fenton system. The same concentration of this extract scavenged 92% DPPH and 95% peroxyl radical during lipid peroxidation. Antioxidant properties were in correlation with the contents of total phenolic compounds (14.49–57.47 mg/g) and flavonoids (5.26–18.62 mg/g) in extracts. The formation of o-semiquinone radicals from rutin and caffeic acid in lipid peroxidation system proved the mechanism (hydrogen donating and/or one-electron reduction) of free-radical scavenging activity. The ESR data demonstrate that methanolic and water extracts of CM possess similar free radicals scavenging and antioxidative activity as synthetic antioxidants BHA.

Domestication of Wild Marigold (Tagetes minuta L.) as a Potential Economic Crop in Western Himalaya and North Indian Plains

Tagetes minuta L., syn. T. glandulifera Schrank grows wild in western Himalaya and is one of the important source of essential oils. The crop has been domesticated by our Institute not only in sub-temperate but also in subtropical zones and farmers have opted Tagetes minuta as an essential oil crop in their cropping system. Four cropping systems have been evolved based on variable sowing and harvesting times yielding varying quality of essential oil. All the four crop practices can be practised in sub-temperate regions while one crop practice is recommended for subtropical regions. Tagetes oil contains three major constituents of monoterpene ketones namely ocimenones E&Z, tagetones E&Z and dihydrotagetone and a hydrocarbon ocimene which are important base materials for synthesizing new aroma molecules. Tagetes oil of desired constituents can be produced by adopting selective crop practice based on experimental findings of present investigation. Ocimene rich crop can be harvested in winter (December–January), dihydrotagetone rich crop in autumn (October–November), tagetone rich crop in summer (June) and ocimenone rich crop can be harvested in short duration autumn–winter (December–January) and summer crops.