Phytochemistry Reviews (v.11, #1)

Phenylphenalenone phytoalexins, will they be a new type of fungicide? by Fernando Echeverri; Fernando Torres; Wiston Quiñones; Gustavo Escobar; Rosendo Archbold (1-12).
Phenylphenalenones represent a kind of phytoalexins produced in leaves and rhyzomes of banana and plantains (Musaceae), as well as in species of other families. These compounds are synthesized in plants by induction with aminoglycosides, or in the first stages of attack by the pathogenic fungus Mycosphaerella fijensis, a causal agent of the disease known as Black Sigatoka, which reduces banana production. In this paper we report the biosynthesis, synthesis and antifungal activities of these kinds of compounds and discus the possibility to use phytoalexins inductors as plant protectants.
Keywords: Black Sigatoka; Disease control; Plant defense; Protectants

Erratum to: Phenylphenalenone phytoalexins, will they be a new type of fungicide? by Fernando Echeverri; Fernando Torres; Wiston Quiñones; Gustavo Escobar; Rosendo Archbold (13-14).

Volatile sesquiterpenes from fungi: what are they good for? by Rolf Kramer; Wolf-Rainer Abraham (15-37).
Fungi can be found in almost all sorts of habitats competing with an even higher number of other organisms. As a consequence fungi developed a number of strategies for protection and communication with other organisms. This review focuses on the increasing number of volatile sesquiterpenes found to be produced by fungal species. The remarkable diversity of this type of volatile organic compound (VOC) within the kingdom fungi is presented and their benefits for the fungi are discussed. The majority of these compounds are hydrocarbons comprising several dozens of carbon skeletons. Together with oxygenated sesquiterpenes they include compounds unique to fungi. Only in recent years the interest shifted from a mere detection and characterization of compounds to their biological function. This review reveals highly diverse ecological functions including interactions with bacteria, other fungi, insects and plants. VOCs act as autoinducer, defend against competing species and play essential roles in attracting pollinators for spreading fungal spores. For many sesquiterpene VOCs sophisticated responses in other organisms have been identified. Some of these interactions are complex involving several partners or transformation of the emitted sesquiterpene. A detailed description of ecological functions of selected sesquiterpenes is given as well as their potential application as marker molecules for detection of mould species. Structures of all described sesquiterpenes are given in the review and the biosynthetic routes of the most common skeletons are presented. Summarizing, this article provides a detailed overview over the current knowledge on fungal sesquiterpene VOCs and gives an outlook on the future developments.
Keywords: Chemical ecology; Chemodiversity; Fungi; Sesquiterpenes; Volatile organic compounds

Andrographis paniculata (Burm.f) Nees is one of the most popular and important medicinal plant of the Orient, and South East Asia. It finds mention in various forms in Indian, Chinese, Malay, Thai, Unani, and Japanese systems of medicine. The plant exhibits anti-cancer, anti-inflammatory, anti-diabetic, anti-hypertensive, anti-venom, cholestatic, hepatoprotective, anti-thrombotic, anti-retroviral, anti-microbial, anti-pyretic, anti-malarial, anti-oxidant, immunomodulatory, and cardioprotective effects. The major active principles contributing to biological activity are diterpene lactones, but flavonoids, xanthones and caffeic acid derivatives also contribute to anti-oxidant, anti-proliferative, anti-atherosclerotic, and anti-malarial effects. As a result of its wide spectrum of pharmacological activity, almost impeccable safety profile, being a widely cultivated medicinal plant, we have collected and compiled various facets of this plant. Extensive datamining of the phytochemistry and pharmacology of Andrographis paniculata revealed more than 50 diterpene lactones, 30 flavonoids, 8 quinic acid derivatives, and 4 xanthones. This review contains information on around 80 isolated compounds, out of which more than half of the compounds have no reported pharmacological activity. Though there are some good reviews available on Andrographis paniculata, the authors of the earlier reviews focused on one or two aspects of the plant and none have attempted to integrate the available information on this plant. This provided us the much needed impetus, warranting a full-fledged and complete review on Andrographis paniculata, one of the most popular and important Oriental medicinal plant.
Keywords: Andrographis paniculata ; Ent labdanes; Flavonoids; Quinic acid derivatives; Ethnopharmacology

Sesquiterpene coumarins by Anna Gliszczyńska; Peter E. Brodelius (77-96).
Plants have a long history as therapeutic tools in the treatment of human diseases and have been used as a source of medicines for ages. In search of new biologically active natural products, many plants and herbs used in traditional medicine are screened for natural products with pharmacological activity. In this paper, we present a group of natural products, the sesquiterpene coumarins isolated from plants, and describe their wide range of biological activity. Sesquiterpene coumarins are found in some plants of the families Apiaceae (Umbelliferae), Asteraceae (Compositae) and Rutaceae. The coumarin moiety is often umbelliferone (7-hydroxycoumarin) but scopoletin (7-hydroxy-6-methoxycoumarin) and isofraxidin (7-hydroxy-6,8-dimethoxycoumarin) are also found. These coumarins are linked to a C15 terpene moiety through an ether linkage. Another group of sesquiterpene coumarins is the prenylated 4-hydroxycoumarins where the link between the coumarin and the C15 terpene moiety is a C–C-bond at carbon 3 of the coumarin moiety. Finally, the prenyl-furocoumarin-type sesquiterpenoids are a separate group of sesquiterpene coumarins based on the suggested biosynthetic pathway. Our relatively limited knowledge on the biosynthesis of sesquiterpene coumarins is reviewed.
Keywords: Farnesyldiphosphate; 4-Hydroxycoumarin; Isofraxidin; Prenylated coumarins; Prenyl-furocoumarin sesquiterpenenes; Scopoletin; Sesquiterpene coumarins; Umbelliferone

Recent advances in elucidating the biological properties of Withania somnifera and its potential role in health benefits by Nadia Alam; Monzur Hossain; Md. Ibrahim Khalil; Mohammed Moniruzzaman; Siti Amrah Sulaiman; Siew Hua Gan (97-112).
Withania somnifera (L.) Dunal (Solanaceae), also known as ashwagandha, is an important medicinal plant that is widely used as a home remedy for several diseases in the Indian subcontinent and other parts of the world. W. somnifera is a dietary supplement composed of various nutrients, polyphenols and alkaloids that have free radical scavenging capacity, as well as other chemical constituents that possess anti-inflammatory, antitumor, anti-stress, antioxidant, immunomodulatory, and rejuvenating properties. The mechanism of action for these properties are not fully understood. W. somnifera also appears to influence the endocrine, cardiopulmonary and central nervous systems. Toxicity studies reveal that W. somnifera can be used without side effects. The findings presented in this review are very encouraging and indicate that this herb should be studied more extensively to confirm these results and to reveal other potential therapeutic effects.
Keywords: W. somnifera ; Chemical constituents; Antioxidant; Therapeutic effects; Toxicity

Biological and chemical properties of Zingiber zerumbet Smith: a review by C. B. Singh; Kh. Nongalleima; S. Brojendrosingh; Swapana Ningombam; N. Lokendrajit; L. W. Singh (113-125).
Numerous researches have been carried out in Zingiber zerumbet Smith. Since 1944 till date. Z. zerumbet is a monocotyledonous perennial medicinal plant belonging to Zingiberaceae family. It is commonly known as shampoo ginger. It has many different local names depending on their area of collection and vegetation. It is called as ‘Singkha’ in Manipuri. Various compounds have been reported to be isolated from Z. zerumbet and they serve a very potent and reliable drug candidate for the various diseases. They have been investigated for its prospects of effectiveness against number of activities in in vitro as well as in vivo and mechanisms that may be involved in chemo preventive measures and various pharmaceutical studies.
Keywords: Anti-cancer; Anti-inflammation; Anti HIV; Anti-AD (Alzheimer’s disease); Multipotential bioactivities

Hypericum sp.: essential oil composition and biological activities by Ana P. Guedes; G. Franklin; Manuel Fernandes-Ferreira (127-152).
Phytochemical composition of Hypericum genus has been investigated for many years. In the recent past, studies on the essential oils (EO) of this genus have been progressing and many of them have reported interesting biological activities. Variations in the EO composition of Hypericum species influenced by seasonal variation, geographic distribution, phenological cycle and type of the organ in which EO are produced and/or accumulated have also been reported. Although many reviews attributed to the characterization as well as biological activities of H. perforatum crude extracts have been published, no review has been published on the EO composition and biological activities of Hypericum species until recently (Crockett in Nat Prod Commun 5(9):1493–1506, 2010; Bertoli et al. in Global Sci Books 5:29–47, 2011). In this article, we summarize and update information regarding the composition and biological activities of Hypericum species EO. Based on experimental work carried out in our laboratory we also mention possible biotechnology approaches envisaging EO improvement of some species of the genus.
Keywords: Bioactive extracts; Biotechnology; Hypericaceae; In vitro; Terpenes