Phytoconstituents from the leaves of Dracaena cochinchinensis (Lour.) S. C. Chen

Dracaenone, a novel type of homoisoflavone: Natural source, biological activity and chemical synthesis

Abstract:

The discovery and synthesis of natural products, especially those possessing novel scaffolds, are crucial to the development of new drugs. Dracaenones are part of homoisoflavone natural products, owning a complex spiro-bridged polycyclic structures bearing benzylic quaternary carbon centers, and some of them reveal considerable biological activity. There have been continuous studies on these compounds due to the rare structure and the important biological properties. However, a systematic summary and analysis for dracaenone is lacking. This review aims to generally summarize the natural source, synthetic strategies and biological activities of dracaenones, moreover, the limitations, challenges, and future prospects were discussed, wishing to provide references for the follow-up study of compounds with similar skeleton.

Natural Bioactive Cinnamoyltyramine Alkylamides and Co-Metabolites

Natural products are a vital source for agriculture, medicine, cosmetic and other fields. Among them alkylamides are a broad and expanding group found in at least 33 plant families. Frequently, they possess a simple carbon skeleton architecture but show broad structural variability and important properties such as immunomodulatory, antimicrobial, antiviral, larvicidal, insecticidal and antioxidant properties, amongst others. Despite to these several and promising biological activities, up to today, only two reviews have been published on natural alkylamides. One focuses on their potential pharmacology application and their distribution in the plant kingdom and the other one on the bioactive alkylamides specifically found in Annona spp. The present review is focused on the plant bioactive cinnamoyltyramine alkylamides, which are subject of several works reported in the literature. Furthermore, the co-metabolites isolated from the same natural sources and their biological activities are also reported.

Inhibition of Proinflammatory Cytokine Release by Flavones and Flavanones from the Leaves of Dracaena steudneri Engl

The leaves of Dracaena steudneri yielded 6 new flavonoids-3,5,7-trihydroxy-6-methyl-3',4'-methylenedioxyflavone (1: ), 5,7-dihydroxy-3-methoxy-6-methyl-3',4'-methylenedioxyflavone (2: ), 3,5,7-trihydroxy-6-methoxy-3',4'-methylenedioxyflavone (3: ), (2S,3S)-3,7-dihydroxy-6-methoxy-3',4'-methylenedioxyflavanone (4: ), 4',5,7-trihydroxy-3,3',8-trimethoxy-6-methylflavone (5: ), (2R) 7-hydroxy-2',8-dimethoxyflavanone (6: )-together with 13 known congeners. Their structures were established using spectroscopic and spectrometric methods including NMR, CD, and HRMSⁿ measurements. The compounds were evaluated for their anti-inflammatory potential through measurement of the levels of cytokines IL-1β, IL-2, GM-CSF, and TNF-α in the supernatant of human peripheral blood mononuclear cells stimulated by lipopolysaccharide. Flavones derivatives 1: -4: with a C-3'/4' methylenedioxy substituent led to a substantial increase in the production of IL-1β and GM-CSF out of 4 pro-inflammatory cytokines relative to LPS control. Quercetin derivatives 5, 11,: and 13: with a hydroxyl group at C-4' inhibited the production of IL-2, GM-CSF, and TNF-α. The presence of a C-2/C-3 double bond in 14: was pivotal to the significantly stronger (0.4 to 27.5% of LPS control) inhibitory effect compared to its dihydro derivative 8: (36.2 to 262.7% of LPS control) against all tested cytokines. It is important to note that the inhibitory activity of 14: was substantially higher than that of the standard drug used, ibuprofen.

Flavonoids and Stilbenoids of the Genera Dracaena and Sansevieria: Structures and Bioactivities

The genera Dracaena and Sansevieria (Asparagaceae, Nolinoideae) are still poorly resolved phylogenetically. Plants of these genera are commonly distributed in Africa, China, Southeast Asia, and America. Most of them are cultivated for ornamental and medicinal purposes and are used in various traditional medicines due to the wide range of ethnopharmacological properties. Extensive in vivo and in vitro tests have been carried out to prove the ethnopharmacological claims and other bioactivities. These investigations have been accompanied by the isolation and identification of hundreds of phytochemical constituents. The most characteristic metabolites are steroids, flavonoids, stilbenes, and saponins; many of them exhibit potent analgesic, anti-inflammatory, antimicrobial, antioxidant, antiproliferative, and cytotoxic activities. This review highlights the structures and bioactivities of flavonoids and stilbenoids isolated from Dracaena and Sansevieria.

Naturally Occurring Homoisoflavonoids: Phytochemistry, Biological Activities, and Synthesis (Part II)

This review documents all the new homoisoflavonoids (HIFs) that have been reported since 2007, whose total number has grown from 159 in 2007 to 295 at the present time. This review contains their structures, biological sources, plant parts they are obtained from, and, if reported, their optical rotations and melting points. The same classification is followed as an earlier review to ease reference to both reviews. This review takes note of the recent revision of plant families that were known to contain HIFs that have now been merged into one big family, Asparagaceae. Homoisoflavonoids also occur in Fabaceae and others. Two taxa, Ophiopogoan japonicus (Asparagaceae) and Caesalpinia sappan (Fabaceae), have been the source of many HIFs. These are briefly summarized. The biological properties of HIFs are also reviewed under the topics such as antioxidant, anti-inflammatory, antimicrobial, antidiabetic, and cytotoxic. The review also surveys the total synthesis of natural HIFs. All new compounds are classified and tabulated following the same style as the previous review.

Dedicated to Professor Andrew Paul Krapcho on the occasion of his 87th Birthday.

Ferulic Acid and Naturally Occurring Compounds Bearing a Feruloyl Moiety: A Review on Their Structures, Occurrence, and Potential Health Benefits

The ubiquitous compound 4-hydroxy-3-methoxycinnamic acid, also known as ferulic acid (FA), constitutes a bioactive ingredient of many foods that may offer beneficial effects against disorders related to oxidative stress, including cancer, diabetes, and neurodegenerative diseases. This review discusses the antioxidant properties of FA, establishing relationships to several biological activities already described for this natural product. Next, 387 naturally occurring compounds, all isolated from plants and published between 1990 and 2015, the structures of which bear 1 or more feruloyl moieties, are covered in this review along with their structural formulas, botanical sources, and bioactivities. The compounds' distribution, structural patterns, bioactivities, and perspectives on food research are also succinctly discussed.