Flavonoids and Triterpenoids Isolated From the Ethyl Acetate Extract of M. quadrangulata Leaves.

The new flavonoid (-)-4'-O-methylepicatechin 5-O-ß-D-glucopyranoside (1), along with four known triterpenes (2-5), a steroid (6), and a flavonoid (7) were isolated from the ethyl acetate extract of Maytenus quadrangulata leaves. The chemical structures of the isolated compounds were determined through analysis of 1D NMR (1H and 13C) spectroscopic data, in addition to 2D NMR and spectrometric (MS) data for compound 1. This is the first report of the isolation of daucosterol (6) and (-)-4'-O-methylepigallocatechin (7) from this species. Compounds 1 and 7 were evaluated against the bacteria Staphylococcus aureus and Klebsiella pneumoniae, but neither exhibited activity even at the highest concentration tested.

Evaluation of Cytotoxicity and Antifungal Activity of Friedelanes from Salacia elliptica Roots.

Plants from Salacia genus are used in traditional medicine for a wide range of diseases. Previous studies reported bioactive pentacyclic triterpenoids from S. elliptica leaves and branches. In this study, the novel pentacyclic triterpenoid 7α,15α-dihydroxyfriedelan-3-one (1) was obtained from the roots of Salacia elliptica, along with seven known compounds: friedelan-3-one (2), friedelan-3ß-ol (3), friedelan-1,3-dione (4), friedelan-3,15-dione (5), 15α-hydroxyfriedelan-3-one (6), 15α,26-dihydroxyfriedelan-3-one (7), and 26-hydroxyfriedelan-3,15-dione (8). Additionally, one steroid, spinasterol (9), was also identified. The chemical structures of all compounds were established through 1 H and 13 C-NMR. Compound 1 was analysed by additional 2D experiments (HMBC, HSQC, COSY, and NOESY) for complete elucidation. Furthermore, the cytotoxicity of compounds 2, 3, 6, 7 and 8 against the A549 lung cancer cells model was evaluated. The flow cytometry analysis revealed a significant cytotoxic activity similar to that exhibited by the triterpenoid lupeol. Additionally, compounds 2, 3, 6, and 7 were tested for in vitro antifungal activity against Candida, Cryptococcus and Sporothrix strains. However, all compounds showed no activity at the tested concentrations.

Laticifer ontogenesis and the chemical constituents of Marsdenia zehntneri (Apocynaceae) latex in a semiarid environment.

MAIN CONCLUSION: Anastomosed laticifers with intrusive growth produce latex containing methyl comate and betulin with economic and ecological value in arid environments. Climatic factors influence laticifer development in the apical meristem and vascular cambium. Latex is a complex emulsion with high medicinal as well as ecological value related to plant survival. Marsdenia zehntneri is a shrubby plant that grows on limestone outcrops in the semiarid regions of Brazil. We sought to characterize the ontogenesis of the laticifers of this species and to relate that process to climatic seasonality and phenology through anatomical, ultrastructural, and micro-morphometric evaluations of the apical meristem and vascular cambium. The histochemistry of the secretory structure was investigated and the chemical composition of the latex was analyzed. Phenological assessments were performed by monitoring phenological events for 1 year. The laticifers network of M. zehntneri permeates the entire primary and secondary body of the plant, providing a wide distribution system of defensive compounds. Its laticifers, of a distinct mixed type (anastomosed, with intrusive growth), are numerous and voluminous in the apical meristem but scarce and minute in the secondary phloem. Latex secretion involves the participation of oleoplasts, polysomes, and dictyosomes. Methyl 2,3-dihydroxy-ursan-23-oate, methyl 3-hydroxy-ursan-23-oate, and betulin are encountered in high proportions in the latex and have ecological and medicinal functions. The development of primary laticifers is related to the resumption of apical meristem activity with increasing day length at the end of the austral winter. The development of secondary laticifers is related to high summer temperatures and rainfall that favor vascular cambium activity. The wide distribution of laticifers, their seasonal pattern of secretion, and their latex composition contribute to the adaptation of M. zehntneri to its natural environment.

Mucilaginous Secretions in the Xylem and Leaf Apoplast of the Swamp Palm Mauritia flexuosa L.f. (Arecaceae).

Mauritia flexuosa palms inhabit wetland environments in the dry, seasonal Brazilian savanna (Cerrado) and produce mucilaginous secretions in the stem and petiole that have a medicinal value. The present study sought to characterize the chemical natures of those secretions and to describe the anatomical structures involved in their synthesis. Chemical analyzes of the secretions, anatomical, histochemical analyses, and electron microscopy studies were performed on the roots, stipes, petioles, and leaf blades. Stipe and petiole secretions are similar, and rich in cell wall polysaccharides and pectic compounds such as rhamnose, arabinose, xylose, mannose, galactose, and glucose, which are hydrophilic largely due to their hydroxyl and carboxylate groups. Mucilaginous secretions accumulate in the lumens of vessel elements and sclerenchyma fibers of the root, stipe, petiole, and foliar veins; their synthesis involves cell wall loosening and the activities of dictyosomes. The outer faces of the cell walls of the parenchyma tissue in the mesophyll expand to form pockets that rupture and release pectocellulose substances into the intercellular spaces. The presence of mucilage in the xylem, extending from the roots to the leaf veins and continuous with the leaf apoplast, and sub-stomatal chambers suggest a strategy for plant water economy.

New Eugenol Glucoside-based Derivative Shows Fungistatic and Fungicidal Activity against Opportunistic Candida glabrata.

A new series of glucosides modified in their saccharide units were synthesized, evaluated against Candida sp., and compared to prototype 1, an eugenol tetracetyl glucoside previously synthesized and shown to be active against Candida glabrata. Among the new glucosides, benzyl derivative 5 was the most promising, showing fungistatic activity at IC50 18.1 µm against Candida glabrata (threefold higher than fluconazole) and fungicidal activity with a low IC90 value of 36.2 µm. Moreover, the cytotoxic activity of compound 5 (CC50 : 580.9 µm), tested in peripheral blood mononuclear cells, suggests its potential as an agent to treat Candida glabrata infections, with a selectivity index of 32. The new eugenol glucoside 5 may be considered as a novel structural pattern in the development of new anti-Candida drugs.