Flavonoids are widely distributed secondary metabolites with different metabolic functions in plants. The elucidation of the biosynthetic pathways, as well as their regulation by MYB, basic helix-loop-helix (bHLH), and WD40-type transcription factors, has allowed metabolic engineering of plants through the manipulation of the different final products with valuable applications. The present review describes the regulation of flavonoid biosynthesis, as well as the biological functions of flavonoids in plants, such as in defense against UV-B radiation and pathogen infection, nodulation, and pollen fertility. In addition, we discuss different strategies and achievements through the genetic engineering of flavonoid biosynthesis with implication in the industry and the combinatorial biosynthesis in microorganisms by the reconstruction of the pathway to obtain high amounts of specific compounds.

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Flavonoids: biosynthesis, biological functions, and biotechnological applications.

Chem. Pharm. Bull.(オピニオン)

https://www.rsc.org/suppdata/np/c2/c2np20049j/c2np20049j.pdf

Natural stilbenoids: distribution in the plant kingdom and chemotaxonomic interest in Vitaceae

Phenylpropanoids are a large class of plant secondary metabolites derived from aromatic amino acids phenylalanine in most plants or tyrosine in partial monocots. It mainly includes flavonoids, mono...

Biosynthesis and Regulation of Phenylpropanoids in Plants

Leishmaniasis is a parasitic disease that presents four main clinical syndromes: cutaneous leishmaniasis (CL), mucocutaneous leishmaniasis (MCL), visceral leishmaniasis/kala azar (VL), and post kala azar dermal leishmaniasis (PKDL). Causative Leishmania are protozoan parasites that are transmitted among mammalian hosts by phlebotomine sandflies. In mammalian hosts, parasite cells proliferate inside the host phagocytic cells as round amastigotes. Infection of sandflies with Leishmania occurs during insect feeding on infected mammalian hosts. After introduction into the insect gut together with the blood meal, Leishmania amastigotes transform into elongated flagellated promastigotes that propagate in the insect gut. A new round of infection is initiated after the infected sandfly takes a blood meal from a naive mammalian host and introduces Leishmania parasites into the bite wound in the host dermis (Scheme 1). More than 20 different Leishmania species have been found to cause human leishmaniasis (Table 1).

Leishmaniasis is endemic in 98 countries and is closely associated with poverty. More than a million new cases are reported per year and 350 million people are at risk of contracting the infection. For the most severe form of leishmaniasis, VL, ∼300 000 new cases are estimated to occur annually resulting in ∼40 000 deaths. Approximately 90% of all VL cases occur in 3 endemic foci: 1. India, Bangladesh, and Nepal; 2. East Africa; and 3. Brazil. In spite of the high prevalence, currently available treatments for leishmaniasis are inadequate. Pentavalent antimonials, the standard treatment for leishmaniasis for many decades, are not efficacious in Bihar (∼60% of VL cases worldwide) any longer due to widespread resistance to the drug in this region. Several new VL treatments have emerged during the past 10–15 years, but each has serious shortcomings (summarized in Table 2). These include paromomycin (injectable, long treatment, region-dependent efficacy), miltefosine (cost, teratogenicity, long treatment), and liposomal amphotericin B (cost, hospitalization, region-dependent efficacy). An additional challenge is represented by patients with HIV/VL coinfections who are more difficult to cure (lower initial and final cure rates), have greater susceptibility to drug toxicity, and have higher rates of death and relapse.

Due to the limitations of the existing treatments, better drugs are urgently needed. Ideally, new VL drugs would be efficacious across all endemic regions, would affect cure in ≤10 days, and would cost <$10 per course (for a complete target product profile for new VL drugs, which was formulated by DNDi, see Table 4).1 Here we describe the disease history and parasite biology followed by a summary of the currently available treatments and, finally, review reports of novel small molecules with antileishmanial activity.

Recent developments in drug discovery for leishmaniasis and human African trypanosomiasis.

Natural stilbenes: an overview

Secondary metabolites from Commiphora opobalsamum and their antiproliferative effect on human prostate cancer cells.

Natural stilbenes have been a hot research topic due to their intricate structures and diverse biological activities. Although their molecular backbone consists only of 1,2-diphenylethylene units, stilbenes show an enormous diversity with regard to the different units present, the degree of polymerisation, and the pattern of oligomer construction. From January 1995 to the end of 2008, more than 400 new naturally occurring stilbenes were isolated and identified, and this review focuses on their structural diversity, distribution, and bioactivity.

Hong-Xiang Lou

Papers

Natural stilbenes: an overview

Secondary metabolites from Commiphora opobalsamum and their antiproliferative effect on human prostate cancer cells.

Natural Stilbenes: An Overview