Cholinesterase Inhibitory Triterpenes from Perovskia atriplicifolia

Non-Alkaloid Cholinesterase Inhibitory Compounds from Natural Sources

Alzheimer's disease (AD) is a severe neurodegenerative disorder of different brain regions accompanied by distresses and affecting more than 25 million people in the world. This progressive brain deterioration affects the central nervous system and has negative impacts on a patient's daily activities such as memory impairment. The most important challenge concerning AD is the development of new drugs for long-term treatment or prevention, with lesser side effects and greater efficiency as cholinesterases inhibitors and the ability to remove amyloid-beta(Aβ) deposits and other related AD neuropathologies. Natural sources provide promising alternatives to synthetic cholinesterase inhibitors and many have been reported for alkaloids while neglecting other classes with potential cholinesterase inhibition. This review summarizes information about the therapeutic potential of small natural molecules from medicinal herbs, belonging to terpenoids, coumarins, and phenolic compounds, and others, which have gained special attention due to their specific modes of action and their advantages of low toxicity and high efficiency in the treatment of AD. Some show superior drug-like features in comparison to synthetic cholinesterase inhibitors. We expect that the listed phytoconstituents in this review will serve as promising tools and chemical scaffolds for the discovery of new potent therapeutic leads for the amelioration and treatment of Alzheimer's disease.

Bioguided identification of triterpenoids and neolignans as bioactive compounds from anti-infectious medicinal plants of the Taira Atacama's community (Calama, Chile)

ETHNOPHARMACOLOGICAL RELEVANCE

Previous ethnobotanical surveys from the north Andean part of Chile, where different ethnic groups are co-existing, with the preeminence of Aymara and Atacama traditions, revealed an extensive domestic use of the local flora. In these communities, traditional medicinal uses are mainly related to the treatment of respiratory, gastro-intestinal and urinary disorders, pain and inflammation, which is closely linked to epidemiological observations.

AIM OF THE STUDY

As these symptoms may be related to infectious diseases, a bioguided evaluation of antibacterial and antifungal activity was conducted on eighteen species selected with the Taira community, in Ollague.

MATERIALS AND METHODS

Screening was performed using a large panel of pathogenic germs involved in the main community acquired infectious diseases, represented by Gram positive and Gram negative bacteria of clinical interest and by human pathogenic fungi, using a bioguided approach.

RESULTS AND CONCLUSIONS

Gram positive strains of clinical interest were highly sensitive to Aloysia deserticola (Verbenaceae) and Krameria lappacea (Krameriaceae) extracts. The bioguided approach led us to identify the isolated neolignan from K. lappacea conocarpan (1), and triterpenoids form A. deserticola (oleanolic acid (6) and ursolic acid (10)), as the main bioactive compounds.

New ursane-type triterpenoids from Clerodendranthus spicatus

Five new ursane-type triterpenoids, spicatusoids A-E (1, 3-6), and three known ones (2, 7, and 8), and a known oleanane-type triterpenoid (9) were isolated from the aerial parts of Clerodendranthus spicatus. Their structures were elucidated by spectroscopic methods. In particular, the structure of 3 including its absolute configuration was confirmed by single-crystal X-ray diffraction analysis. Cell viability of all the compounds against rat kidney fibroblast cells (NRK-49F) with or without TGF-β1 induction and human cancer cells (HL-60, SMMC-7721, A-549, MCF-7, and SW-480) was examined by using MTT or MST assays. It was found that, with exception of 1, all the tested compounds could inhibit cell proliferation in TGF-β1 induced NRK-49F cells with compounds 2 being most active.

Six New Triterpene Derivatives from Aralia chinensis Var. dasyphylloides

Aralia chinensis var. dasyphylloides is widely distributed in China and used as a traditional herbal medicine for the treatment of digestive and immune system diseases. The present study aimed to search for novel oleanolic-type triterpenoids in low-polarity fractions. Six new triterpene derivatives (1-6), together with two known compounds were isolated from the barks of A. chinensis var. dasyphylloides. Their structures were elucidated by 1D- and 2D-NMR spectroscopic analysis and chemical methods. They were identified as 3-oxo-oleana-11,13(18)-dien-28,30-dioic acid (1), 30-hydroxy-3-oxo-oleana-11,13(18)-dien-28-oic acid (2), 3β-hydroxy-oleana-11,13(18)-dien-28-oic acid-28-O-β-d-glucopyranoside (3), 3β,30-dihydroxy-oleana-11,13(18)-dien-28-oic acid-28-O-β-d-glucopyranoside (4), 3β-hydroxy-oleana-11,13(18)-dien-28-oic acid-3-O-β-d-xylopyranosyl-(1 → 2)-β-d-glucopyranoside (5), 3β,29-dihydroxy-oleana-9(11),12-dien-28-oic acid-28-O-β-d-glucopyranoside (6), namely, araliachinolic acids I and II and araliachinosides I-IV. The cytotoxicity of the isolated compounds was tested against HepG2, A549, SGC7901, and MCF7 cell lines, but no apparent activity was observed at a concentration of 50 μM.

Phytochemistry and pharmacological activities of the genus Prunella

Prunella is a genus of perennial herbaceous plants in the Labiatae family. There are approximately 15 species worldwide, distributed widely in the temperate regions and tropical mountains of Europe and Asia. In the genus Prunella, P. vulgaris is the most studied, following a several thousand-year history as a traditional antipyretic and antidotal Chinese herb. Furthermore, since ancient times, P. vulgaris has been widely used as a cool tea ingredient and consumed as a vegetable. The genus Prunella contains triterpenoids and their saponins, phenolic acids, sterols and associated glycosides, flavonoids, organic acids, volatile oil and saccharides. Modern pharmacological studies have revealed that Prunella possess antiviral, antibacterial, anti-inflammatory, immunoregulatory, anti-oxidative, anti-tumor, antihypertensive and hypoglycemic functions. The active components related to these functions are mainly triterpenoids, phenolic acids, flavonoids and polysaccharides. This review mainly summarizes recent advances in traditional usage, chemical components and pharmacological functions.