Maytenus distichophylla and Salacia crassifolia: source of products with potential acetylcholinesterase inhibition

ABSTRACT The phytochemical study of the extract leaves from Maytenus distichophylla Mart. and Salacia crassifolia (Mart. ex Schult.) G. Don, Celastraceae, resulted in the isolation of 3-oxofriedelane, 3β-hydroxyfriedelane, 3β,24-dihydroxyfriedelane, 3-oxo-28,29-dihydroxyfriedelane, two mixtures of pentacyclic triterpenes (α-amyrin with β-amyrin and 3β-stearyloxy-urs-12-ene with 3β-stearyloxy-olean-12-ene), 3β-palmityloxy-urs-12-ene, the steroid β-sitosterol and its glycosylated derivative β-glucosyl-β-sitosterol, tritriacontanoic acid and the natural polymer gutta percha. The chemical structures of these constituents were established by IR, 1H and 13C NMR spectral data. Crude extracts, the mixtures of triterpenes and the isolated constituents were subjected to in vitro acetylcholinesterase inhibitory evaluation. Acetylcholinesterase inhibitory effect was observed for crude chloroform extract leaves from M. distichophylla (100%) and S. crassifolia (97.93 ± 5.63%) and for the triterpenes 3β,24-dihydroxyfriedelane (99.05 ± 1.12%), 3-oxo-28,29-dihydroxyfriedelane (90.59 ± 3.76%) and 3β-palmityloxy-urs-12-ene (97.93 ± 1.47%). The percent inhibitions induced by these natural products were very similar to those produced by physostigmine (93.94 ± 2.10%) a standard acetylcholinesterase inhibitor. Therefore, these results open perspectives for the use of these species as source of compounds with similar physostigmine pharmacological effect.

Immunomodulatory properties of green propolis.

Propolis is a resinous material collected by honeybees from numerous plants and serves as a defense against intruders. Because of its relevant curative properties, it is now gaining popularity in health foods and in cosmetic products. Understanding the underlying molecular mechanisms of phytochemicals has become a good strategy in bioprospection for new anti-inflammatory compounds. The biological activity of propolis derives from its high levels of phenolic acids, while flavonoids are thought to account for the activity of propolis extracts. The comprehension of the relationship between propolis and the immune system has progressed in the last years, recent articles have provided important contributions to this investigation field. Studies have shown that propolis suppressed the "IL-6-induced phosphorylation of signal transducer and STAT3", an essential cytokine-activated transcription factor in Th17 development. Therefore, action mechanisms of "propolis on Th17 differentiation could be instrumental in controlling disturbed cytokine networks in inflammation, autoimmune diseases, and infections." The use of propolis has been proposed in some patents as: WO201363714; CN102885854, WO2013142936, US20130266521, and US20130129808, which are related to the treatment of dental diseases; adjuvant in anti-cancer treatment; in cosmetic products; as an anti-inflammatory agent and natural antibiotic. Although there are many publications regarding the propolis efficacy, its applicability to human health and mechanisms of action are not completely understood, creating opportunities for new studies.

The anti-oxidant properties of isothiocyanates: a review.

Cruciferous vegetables, such as broccoli and watercress, have been studied extensively aiming to evaluate their chemopreventive properties. Some of them have already been established using animal models. The ITCs induce Phase II enzymes related to detoxification processes of chemical carcinogens to prevent the start of carcinogenesis. They also exhibit antitumor activity at post-initiation phase, suggesting their additional role(s) in cancer prevention. Sulforaphane is the most extensively studied isothiocyanate, focused in its anti-tumoral activity and it is mainly found in great amounts in broccoli and other cruciferous. In a dose dependent manner, ITCs inhibit the cell viability of human cervical cancer cells, human pancreatic cancer cells, human hepatocellular carcinoma cells, human ovarian cancer cells, and have antiinflammatory properties in the treatment of human T-cell leukemia cells. This protective effect may be due to improved antioxidant status. Although the health effects of diet in humans are generally considered promising, there are definite challenges and limitations of the current data in better understanding of the molecular mechanisms responsible for this effect, together with the possible interactions between different dietary constituents. The survey of relevant patents on the use of isothiocyanates such as sulforaphane for cancer and cardiovascular diseases treatments is also included in this review.

Maytenus salicifolia Reissek, Celastraceae: triterpenes isolated from stems and antioxidant property of extracts from aerial parts

Six pentacyclic triterpenes were isolated from hexane extract of stems of Maytenus salicifolia Reissek, Celastraceae: 30-hydroxyfriedelan-3-one (1), 3,16-dioxofriedelane (2), friedeline (3), lupeol (4), betuline (5) and lup-20(29)-en-3,30-diol (6). The structure each one was established on the basis of detailed ¹H and 13C NMR spectral investigation and by comparison with the respective literature values. For compound 1, the complete 2D NMR (HMBC, HMQC and NOESY) spectral data were herein reported for the first time. Compounds 1, 2, 5 and 6 were isolated for the first time from this plant. Antioxidant activity is described for some extracts from species of the Celastraceae family, then, the extracts from aerial parts of M. salicifolia were evaluated in relation to antioxidant potential using the DPPH method. Compared to quecertin, the AcEt extract (EAF) from leaves, AcEt (EAPF) and MeOH (EMPF) from pulp fruit and AcEt (EAT) and MeOH (EMT) from stems showed significant antioxidant property.