Occurrence and stress response of N-methylproline compounds in Tamarix species

Phytochemical and pharmacological properties of the genus Tamarix: a comprehensive review

The genus Tamarix in the Tamaricaceae family consists of more than 100 species of halophyte plants worldwide that are mainly used to improve saline-alkali land and for coastal windbreaks, sand fixation, and afforestation in arid areas. A considerable number of species in this genus are also used as traditional medicines to treat various human diseases, especially in Asian and African countries. This review presents a comprehensive summary of 655 naturally occurring compounds derived from the genus Tamarix, categorized into flavonoids (18.0%), phenols (13.9%), tannins (9.3%), terpenoids (10.5%), essential oils (31.0%), and others (17.3%). The investigation revealed that the crude extracts and phytochemicals of this genus exhibited significant therapeutic potential, including anti-inflammatory, anti-Alzheimer, anticancer, antidiabetic, antibacterial, and antifungal activities. Six species of Tamarix have anticancer effects by causing cancer cell death, inducing autophagy, and stopping cell division. Seven species from the same genus have the potential for treating diabetes by inhibiting α-glycosidase activity, suppressing human islet amyloid polypeptide, regulating blood glucose levels, and modulating autophagy or inflammation. The focus on antibacterial and antidiabetic effects is due to the presence of volatile oil and flavonoid components. Extensive research has been conducted on the biological activity of 30 constituents, including 15 flavonoids, 5 phenols, 3 terpenoids, 1 tannin, and 6 others. Therefore, future research should thoroughly study the mechanisms of action of these and similar compounds. This is the most comprehensive review of the phytochemistry and pharmacological properties of Tamarix species, with a critical assessment of the current state of knowledge.

Iridoids and Amino Acid Derivatives from the Paraguayan Crude Drug Adenocalymma marginatum (ysypó hû)

The crude drug ysypó hû (Adenocalymma marginatum DC., Bignoniaceae) is used traditionally by the Guarani of Eastern Paraguayan as a male sexual enhancer. The aim of the present study was to identify the main constituents of the crude drug and to evaluate the in vitro inhibitory activity towards the enzyme phosphodiesterase-5 (PDE-5). The main compounds were isolated by counter-current chromatography (CCC). The metabolites were identified by spectroscopic and spectrometric means. The chemical profiling of the extracts was assessed by high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS/MS). The crude extract and main isolated compounds were tested for their PDE-5 inhibitory activity using commercial kits. The iridoid theviridoside and 4-hydroxy-1-methylproline were isolated as the main constituent of the crude drug. Four chlortheviridoside hexoside derivatives were detected for the first time as natural products. Chemical profiling by HPLC-MS/MS led to the tentative identification of nine iridoids, six phenolics, and five amino acids. The crude extracts and main compounds were inactive towards PDE-5 at concentrations up to 500 µg/mL. Iridoids and amino acid derivatives were the main compounds occurring in the Paraguayan crude drug. The potential of ysypó hû as a male sexual enhancer cannot be discarded, since other mechanisms may be involved.

A New Flavanone from the Leaves ofChromolaena odorata

Chromolaena odorata (Syn: Eupatorium odoratum) is a perennial plant belonging to the Asteraceae family. Extracts of C. odorata have shown strong anti-oxidant and moderate anti-adipogenenesis activities. Detailed phytochemical investigation of C. odorata led to the isolation of 21 secondary metabolites, which include a new flavanone (3), and a chalcone, 3,2′-dihydroxy-4,4′,5′,6′-tetramethoxychalcone (2), reported for the first time from a natural source, besides three known compounds 1, 4 and 5, all of which are reported for the first time from C. odorata. Some of these compounds exhibited potent anti-oxidant and anti-adipogenesis activities and these may be partly responsible for the activity of the extract.

Identification of drought-responsive compounds in potato through a combined transcriptomic and targeted metabolite approach

Two potato clones (Solanum tuberosum L.) of the Andean cultivar group, called Sullu and SS2613, with different drought-tolerance phenotypes were exposed to a continuously increasing drought stress in a field trial. At the physiological level, while relative leaf water contents were similar in both clones, osmotic potential was lower in Sullu and declined more strongly during drought compared with SS2613. In the drought-stressed plants, tuber yield was reduced by about 70% compared with control plants in both clones. Potato cDNA microarrays and target metabolite analysis were performed on leaves sampled at several time-points after the onset of drought. At the transcriptomic level, photosynthesis-related genes were already strongly repressed in Sullu after 28 d of withholding irrigation and even more strongly after a longer stress duration, whereas, in SS2613, repression occurred only after 49 d of soil drying; similarly, a strong perturbation of carbohydrate-related genes was observed in Sullu. At the metabolite level, differential accumulation of osmotically active solutes was observed between the two cultivars; indeed, in Sullu, contents of galactose, inositol, galactinol, proline, and proline analogues were higher upon drought stress compared with SS2613. These results point to different drought responses in the cultivars at the leaf level, with, however, similar tuber yield reductions. The previously shown tolerant clone Sullu lost part of its tolerance under the experimental conditions used here; it was, however, able to maintain an absolute yield three times higher than SS2613.