Cytotoxic withanolides from Datura innoxia.

Chemical investigation of the aerial parts (except fruits) of the medicinal, hallucinogen and toxic plant Datura innoxia Mill. [Solanaceae] led to the isolation of the new withanolide, dinnoxolide A (1), along with the known compounds 21,27-dihydroxy-1-oxowitha-2,5,24-trienolide (2), daturamalakin B (3) and withametelin (4). Their structures were established by analysis of their spectroscopic data, including 1D and 2D NMR experiments and MS. Compounds 2 and 3 were isolated as natural products for the first time and the name dinnoxolide B was given to compound 2. The four withanolides showed in vitro cytotoxic activity against U251 (glioblastoma) and SK-LU-1 (lung adenocarcinoma) human cancer cell lines, with IC50 values ranging from 1.2 to 19.6 µM, and also against the noncancerous monkey kidney cell line (COS-7), with IC50 values ranging from 5.0 to 19.7 µM. Compound 4 was two times more active than the reference compound, etoposide, against lung adenocarcinoma cells.

Datura innoxia plants hydroponically-inoculated with Agrobacterium rhizogenes display an enhanced growth and alkaloid metabolism.

BACKGROUND: The production of secondary metabolites through the culture of entire plants is of great interest. Soilless culture, such as hydroponics, enables the control of plant growth and metabolism. Specific environmental conditions must be developed to maximize the productivity of medicinal plants used as efficient natural bioreactors. METHODS: The nutrient solution of newly established hydroponic cultures ofDatura innoxia Mill. were inoculated with Agrobacterium rhizogenes (A.r.) wild strains (TR7, TR107, 11325 or 15834). Growth and the alkaloid contents of roots and aerial parts were analyzed. Axenic cultures were also performed with modified TR7 strains containing the egfp or gus reporter gene. In vitro isolated root cultures enabled the phenological and molecular demonstration of gene transfer. RESULTS: A.r.TR 7 led to a greater improvement in plant secondary metabolism and growth. Positive expression of the reporter genes occurred. Isolation and subculture of some of the roots of these plants showed a hairy root phenotype; molecular tests proved the transfer of bacterial genes into the roots isolated from the plants. CONCLUSIONS: Hyoscyamine and scopolamine productivity is enhanced after A.r. inoculation in the nutrient solution of hydroponic plants. Transformation events occur in the original roots of the plants. This leads to chimeric plants with a part of their roots harboring a hairy root phenotype. Such semi-composite plants could be used for successful specialized metabolite bioproduction in greenhouses.

Extraction optimization of medicinally important metabolites from Datura innoxia Mill.: an in vitro biological and phytochemical investigation.

BACKGROUND: The present study aims to probe the impact of polarity dependent extraction efficiency variation on pharmacological spectrum of Datura innoxia Mill. in order to reconnoiter its underexplored therapeutic potential. METHODS: A range of solvent extracts was subjected to phytochemical and biological assays to find the most proficient solvent system and plant part for each type of bioactivity. Total phenolic and flavonoid contents were determined colorimetrically and specific polyphenols were quantified by HPLC-DAD analysis. The samples were biologically evaluated by employing multimode antioxidant, cytotoxic, protein kinase inhibition and antimicrobial assays. RESULTS: Among all the solvents used, maximum percent extract recovery (33.28 %) was obtained in aqueous leaf extract. The highest amount of gallic acid equivalent phenolic and quercetin equivalent flavonoid content was obtained in the distilled water and ethyl acetate-ethanol extracts of leaf i.e., 29.91 ± 0.12 and 15.68 ± 0.18 mg/g dry weight (DW) respectively. Reverse phase HPLC-DAD based quantification revealed the presence of significant amounts of catechin, caffiec acid, apigenin and rutin ranging from 0.16 to 5.41 mg/g DW. Highest DPPH radical scavenging activity (IC50 = 16.14 µg/ml) was displayed by the ethyl acetate-acetone stem extract. Maximum total antioxidant capacity and reducing power potential were recorded in the aqueous leaf and ethyl acetate stem extracts i.e., 46.98 ± 0.24 and 15.35 ± 0.61 mg ascorbic acid equivalent/g DW respectively. Cytotoxicity against brine shrimps categorized 25 % of the leaf, 16 % of the stem and 8.3 % of the fruit extracts as highly potent (LC50 ≤ 100 µg/ml). Significant cytotoxicity against human leukemia (THP-1) cell line was exhibited by the chloroform and n-hexane fruit extracts with IC50 4.52 and 3.49 µg/ml respectively. Ethyl acetate and methanol-chloroform extracts of leaf and stem exhibited conspicuous protein kinase inhibitory activity against Streptomyces 85E strain with 22 mm bald phenotype. A noteworthy antimicrobial activity was exhibited by leaf extracts against Micrococcus luteus and n-hexane fruit extract against Aspergillus niger (MIC 3.70 and 12.5 µg/ml respectively). CONCLUSION: Multiple solvent system is a crucial variable to retrieve pharmacological potential of medicinal plants and D. innoxia can be envisaged as a novel source of natural antioxidants, antimicrobials and anticancer compounds.

Variation in herbivore and methyl jasmonate-induced volatiles among genetic lines of Datura wrightii.

Many plant species produce volatile organic compounds after being damaged by herbivores. The production of volatiles also may be induced by exposing plants to the plant hormone, jasmonic acid, or its volatile ester, methyl jasmonate. This study addresses the induction of the production volatile organic compounds among genetic lines of Datura wrightii. Within populations, some plants produce glandular trichomes, whereas others produce nonglandular trichomes, and trichome phenotype is controlled by a single dominant gene. Glandular trichomes not only confer resistance to some herbivorous insects, but they also inhibit many natural enemies of those herbivores. Because of the potential benefit of natural enemies that use volatile cues to find individuals of the non-glandular phenotype, it is reasonable to ask if plants of D. wrightii that differ in trichome morphology might produce different blends of volatile compounds. Volatile compounds were collected from eight genetic lines of plants that had been backcrossed for three generations. Volatiles were collected from pairs of sibling plants before and after insect damage or treatment with methyl jasmonate. Within each pair, one sib expressed glandular trichomes and the other expressed nonglandular trichomes. Overall, plants produced an array of at least 17 compounds, most of which were sesquiterpenes. Total production of volatiles increased from 3.9- to 16.2-fold among genetic lines after insect damage and from 3.6- to 32-fold in plants treated with methyl jasmonate. The most abundant compound was (E)-beta-caryophyllene. This single compound comprised from 17 to 59% of the volatiles from insect-damaged plants and from 24 to 88% of the volatiles from plants treated with methyl jasmonate, depending upon genetic line. The production of (E)-beta-caryophyllene by the original male parents of the eight genetic lines was significantly related to the mean production of their third-generation backcross progeny indicating that the variation in the production of (E)-beta-caryophyllene was inherited. Blends did not differ qualitatively or quantitatively between sibs expressing glandular or nonglandular trichomes.