Hussein Al-Amier

Influence of Salt Stress on Growth and Essential Oil Production in Peppermint, Pennyroyal, and Apple Mint

ABSTRACT The effect of salt stress on the growth and chemical composition of the essential oils of peppermint (Mentha x piperita L.), pennyroyal (Mentha pulegium L.) and apple mint (Mentha suaveolens Ehrh.) was investigated. Plantings in a greenhouse were irrigated with full-strength Hoaglunds solution containing 0, 1.5, 3.0, or 4.5 g/L− 1 of NaCl for 74 days. Under salt stress, reduced growth was observed in all three species, although differences in sensitivity to the stress were noted. The fresh weight of apple mint was reduced more, as compared with respective untreated controls, than the other tested species at all the tested salinity levels. Essential oil yields per plant under salt stress were reduced in all three species, as compared with untreated controls not under salt stress. The lower oil yields were a function of smaller plant size and, for peppermint and apple mint, the lower concentration of oil within the tissue as compared with untreated controls. In pennyroyal, the oil concentration in the plant tissue under salt stress increased as compared with untreated controls, suggesting that oil synthesis and/or oil degradation processes were less sensitive to salt stress than similar processes in peppermint and apple mint. Within the essential oil, the relative level for various constituents increased, decreased, or did not change in all three tested plant species under salt stress as compared with nonstressed control plants.

Essential Oil and Enzyme Activity in Spearmint Under Salt Stress

The role of glucose-6-phosphate dehydrogenase (G6PD), catalase (CAT), and proline dehydrogenase (PDH) activity were investigated in a spearmint (Mentha spicata) clonal line tolerant to salt stress grown for 8 weeks in a Hoaglands nutrient solution containing salt (200 mM NaCl). G6PDH, CAT, PDH, proline, chlorophyll, and total phenolics were measured using spectrophotometry. As compared with unstressed controls, G6PDH activity increased over time in plants under salt stress except for the last 2 weeks of the experimental period. The PDH and the antioxidative enzyme CAT were inhibited in salt-stressed plants. Free proline accumulation increased under the salt stress as compared with controls, probably due to inhibition of PDH.

Evaluation of Extraction Methods for Isolation and Detection of Formononetin in Black Cohosh (Actaea racemosa L.)

Black cohosh (Actaea racemosa L.) is a medicinal plant from which extracts of the roots and rhizomes (commonly known as rhizomes) have become a popular remedy for the relief of menopausal symptoms. While the chemical constituents responsible for the medicinal properties of the plant are unknown, extracts of the rhizomes are known to contain cycloartane triterpene glycosides, phenolics, and flavonoids. The possible presence of the phytoestrogenic isoflavone formononetin (7-hydroxy-4’-metoxy-isoflavone), however, could indicate that using black cohosh by women could enhance the risk of breast cancer similar to the risks associated with estrogen. Analyses for formononetin in black cohosh over the past several years, however, has been conflicting with some laboratories reporting the constituent in the rhizomes and others not. To determine whether these differences could be due to differences in the extraction and analysis methodology, extractions of the rhizomes were made with methanol, ethanol, and isopropanol and purified using a SPE C18 and DEAE Sephadex A-25 column. LC-MS-MS was used to detect the presence of formononetin using a Waters 2690 Alliance HPLC coupled with a Micromass Quattro 11 triple-quadruple mass spectrometer equipped with an electrospray source operated in the positive/negative ionization mode. The mass spectra of black cohosh constituents were obtained by infusing standard solutions into the mass spectrometer or by LC-MS, LC-MS-MS with product ion scanning. Formononetin at a concentration of <125 ng g -1 was identified in methanol extracts using LC-MS-MS with a microbore C18 column and with the ion pairs of m/z 269-253, 269-225, and 269-197. Introduction In the United States, some 25 to 40 percent of menopausal women have traditionally used some form of hormone replacement therapy (HRT) during or following menopause (Handa et al., 1996; Keating, et al., 1999; Stehman-Breen, et al., 1999). Reports during the past few years of adverse effects from HRT (Bush and Whitemen, 1999; Grodstein, et al., 1996), such as increased risk of breast and uterine cancer, have caused nationwide concern (Beckner, 2002). As result of the warnings about HRT, many women have been using botanical dietary supplements as an alternative to HRT with one of the more popular of these supplements being the roots and rhizomes (commonly referred to as rhizomes) of black cohosh (Actaea racemosa L.), a perennial plant native to the eastern woodlands of North America that was used by Native Americans as a therapeutic agent (Wood, 2000). Formononetin, an isoflavone, was initially proposed to be responsible for the pharmacological activity of black cohosh due to the potential phytoestrogenic activity of the compound (Kennely, et al., 2002). Such estrogenic activity, however, could Al-Amier et al.: Evaluation of Extraction Methods for Isolation and Detection of F

Comparative Evaluation of the Volatile Constituents in Some Verbena Species Cultivated in Egypt

ABSTRACT The composition of the volatile constituents of the fresh aerial parts of Verbena venosa Gill & Hook, Verbena bonariensis L., Verbena hybrida Vass. and Verbena supina L., were investigated by GC and GC-MS. Trans-isoelemicin was the major component (18.90% w/w) of the volatile constituents in Verbena venosa, while dihexyl phthalate, was the major component of the volatile constituents in Verbena bonariensis (48.11% w/w), Verbena hybrida (48.57% w/w), and Verbena supine (45.10% w/w). The essential oil from all the tested Verbena species exhibited significant antimicrobial and antifungal activities.

Use of Mutations to Improve Essential Oil Yield and Constituency in Pennyroyal

ABSTRACT Mutations were induced in two clonal lines of pennyroyal (Mentha pulegium L.) differing in response to the proline analog L-azetidine-2-carboxylic acid (A2C), using γ-rays and ethyl methane sulfonate (EMS). Mutants with increased biomass, an increased essential oil concentration, and increased levels of pulegone within the essential oil, compared with unmutated controls, were successfully developed in the clonal line susceptible to A2C using both the γ-rays and the EMS. Positive mutation responses were observed in almost all the mutants. A mutant developed using γ-ray treatment had a 16 percent increase in dry weight, a 9 percent increase in essential oil, and a 43 percent increase in pulegone compared with an unmutated control. A mutant developed using EMS appeared to be the best overall mutant with a 32 percent increase in dry weight, a 17 percent increase in essential oil, and a 47 percent increase in pulegone.