Evaluation of inorganic contaminants emitted from automobiles and dynamics in soil, dust, and vegetations from major highways in Pakistan.

The deposition of toxic metals in the ecosystem contributes to the exposure and bioaccumulation of metals in the food chain, thus affecting human health. This study aimed to access the distribution of metal pollution emitted from automobiles in the dust, soil, and plant samples collected from the roadsides of national highways. Furthermore, metals were also determined in fuels and vehicular emissions. High contents of Pb, Cd, Cr, Cu, Fe, Mn, and Zn were found in roadsides as compared to control (35 km away from roads). The comparison among plants indicated that Calotropis procera and Rumex dentatus contained significantly higher metals than other plants. The concentrations of Pb, Cd, Cr, and Fe in plants were above the safe limits of the WHO/FAO. Significant and positive correlations were found between Cr, Cu, Fe, Pb, and Zn in the dust and soil samples and Cd and Cr in dust and plants. According to the results of the PCA analysis, all metals formed the first two components explaining 89.5% of the total variance. The source of these metals was attributed to automobile exhaust and dust depositions. The findings of the present study suggest that roadside plants are heavily infested with heavy metals due to vehicular smoke pollution, so the consumption of vegetation facing vehicular pollution may lead to certain physiological disorders and diseases. Graphical abstract.

Isolation of nematicidal compounds from Tagetes patula L. yellow flowers: structure-activity relationship studies against cyst nematode Heterodera zeae infective stage larvae.

Bioassay-guided isolation studies on the extracts of yellow flowers of Tagetes patula L. against the Heterodera zeae were carried out to identify phytochemicals lethal to this economically important cyst nematode. In vitro investigation of a polar extract and fractions showing activity led to the isolation of phenolic compounds (flavonoids and phenolic acids). In the nonpolar extract, a few fatty acids, their methyl esters, and thiophenes (including α-terthienyl) were detected. In studies of compounds obtained commercially, α-terthienyl and gallic and linoleic acids showed 100% mortality at concentrations of 0.125% after 24 h. Assessment of structure-activity relationships revealed that an increase in the number of hydroxyl groups in phenolic acids increased the activity; with fatty acids, activity depended on chain length and the number and position of double bonds. Crude extracts of the flowers of different colors also have promising activity.

Bioassay-guided isolation of antioxidant agents with analgesic properties from flowers of Tagetes patula.

CONTEXT: Tagetes patula L. is one of the French marigold group of the Asteraceae family. It is recognized in folklore for its medicinal and pesticidal properties. OBJECTIVE: In search of more effective, but non-toxic compounds with antioxidative potential led to the bioassay guided isolation studies on the extracts of T. patula. MATERIALS AND METHODS: The bioassay on Tagetes patula flowers were carried out guided by in vitro antioxidant activity using DPPH assay. A minor but proven plant constituent methyl protocatechuate (1) was isolated by column chromatography, while patuletin (2) and patulitrin (3) obtained in bulk by employing solvent partition of methanol extract. Derivatization of patuletin into benzoyl, cinnamoyl and methyl was conducted to establish the structure activity relationship (SAR). Analgesic activity of compound 2 was evaluated using acetic acid-induced writhing test and hot-plate test in mice. The toxicity of methanol extract and compound 2 were also determined. RESULTS: Polar extracts, fractions and phases demonstrated better antioxidant activity. The synthetic methyl protocatechuate (1) showed IC(50) value of 2.8 ± 0.2 µg/mL, whereas patuletin (2) (IC(50) = 4.3 ± 0.25 µg/mL) was comparable to quercetin and rutin but significantly better than patulitrin (3) (IC(50) = 10.17 ± 1.16 µg/mL). Toxicity test for the methanol extract and compound 2 did not elicit any behavioral changes or cause mortality in mice. Compound 2 also demonstrated mild analgesic property. DISCUSSION AND CONCLUSION: These findings demonstrate that the plant polar extracts and fractions possess significant antioxidant property with non-toxic effect. Compound 1 is a genuine plant constituent of T. patula.

Temperature and solvent dependent NMR studies on mangiferin and complete NMR spectral assignments of its acyl and methyl derivatives.

By employing concerted 1 and 2D NMR techniques, exact NMR spectral assignments have been made of the acyl (2-7) and methyl (8 and 9) derivatives of mangiferin (1) isolated from the leaves of Bombax ceiba. Derivatives 2, 8 and 9 have been reported in literature, while 3-7 represent new compounds. The acetates 2 and 3 were found to be unstable and were converted into the same penta-acetate 4 at room temperature. Extensive NMR studies on mangiferin (1) and its derivatives showed that H-4 exchanges with deuterium of the solvent molecule more easily. This exchange under acidic conditions occurred at that position (C-4) where electrophilic substitution reactions can easily take place. This is the first report describing the exchange of C-4 proton of mangiferin (1), or any other xanthone, with deuterium of solvent molecules.

Hypotensive and toxicological study of citric acid and other constituents from Tagetes patula roots.

Study of the effects of the methanolic extract of Tagetes patula roots on blood pressure led to the isolation of well known citric (1) and malic acid (7) as hypotensive, and pyridine hydrochloride (4) as hypertensive constituents of the plant along with a new constituent, 2-hydroxy, 5-hydroxymethyl furan (9). Citric acid and malic acid caused 71% and 43% fall in Mean Arterial Blood Pressure (MABP) of rats at the doses of 15 mg/kg and 30 mg/kg respectively while pyridine hydrochloride produced 34% rise in the MABP of rats at the dose of 30 mg/kg. LD50 and LD100 of citric acid in mice have been determined as 545 mg/kg and 1000 mg/kg, respectively.