Naturally Occurring Homoisoflavonoids: Phytochemistry, Biological Activities and Synthesis

Abstract

This review covers the phytochemical, biological properties, and synthesis of naturally occurring homoisoflavonoids. Homoisoflavonoids are a very important class of secondary metabolites whose numbers have grown from 20 in 1981 to 157 at the present time. They are found to occur in seven plant families. For the purpose of this review they are classified into five groups: 3-benzylchroman-4-ones, 3-benzylflavans, Δ3,9 and Δ2,3 3-benzylchroman-4-ones, benzocyclobutenes (scillascillins) and rearranged homoisoflavonoids (brazilin and related compounds). Biosynthetically, the 3-benzylchroman-4-ones and the 3-hydroxy-derivatives have been shown to arise from a chalcone precursor (sappanchalcone) and there is strong evidence that this isolable intermediate can be converted into the diverse structures such as the benzocyclobutenes (scillascillins) and the rearranged, brazilin-type compounds. Homoisoflavonoids possess a wide range of biological activities, including, antimicrobial, antimutagenic, anti-inflammatory, antidiabetic, etc, properties. The review also surveys the chemical synthesis of natural homoisoflavonoids. Analytical methods for the determination of these important metabolites are also reviewed. The last section is devoted to a brief review of the diagnostic NMR spectroscopic features of homoisoflavonoids. A comprehensive Table has also been compiled listing all known metabolites, their sources, melting points and optical rotation values (where available) and references.

Sappanin-type homoisoflavonoids from Sansevieria trifasciata Prain

“…A plausible biogenetic pathway to the formation of compounds 1 and 2 from sappanchalcone 5 was proposed because biosynthetically, the 3-benzylchroman-4-one and the 3-hydroxy-derivatives have been shown to arise from this chalcone (Abegaz et al, 2007). Sappanchalcone was previously isolated from Caesalpinia japonica Sieb.…”

“…Since some homoisoflavonoids were shown to exhibit potent cytotoxicity (Abegaz et al, 2007;Lin et al, 2014), compounds 1 and 2 were evaluated for their antiproliferative activity on HeLa cells and no considerable effect was observed when compare to 5-FU (fluorouracil) used as positive control.…”

“…Sappanin-types are the ones bearing a 3-benzyl chromane skeleton, in which the benzopyran and aromatic rings are connected via one carbon. Up to now, about 240 natural occurring homoisoflavonoids have been reported, distributed mainly in various parts of plants of the families Asparagaceae and Fabaceae (Abegaz et al, 2007;Lin et al, 2014). They have been reported to possess a broad range of bioactivities including anti-microbial, anti-mutagenic, anti-oxidant, immunomodulatory, anti-diabetic, cytotoxic, anti-angiogenic, vaso-relaxant, and anti-inflammatory effects (Lin et al, 2014).…”

Review on Ethnomedicinal and Pharmacological Uses of <i>Echinops kebericho</i> Mesfin in Ethiopia

“…Echinops kebericho has been used for curative and therapeutic properties intreating various infectious and non infectious diseases such as fever, headache, stomachache, malaria, and cough [15]. In the pharmacological action E.keberichoroot extracts have also been reported forantihelmintic, antitumor, antimutagenic, antibacterial and fungicidal properties [16,17]. In addition, extracts and essential oils of the roots were shown to have antimicrobial, antihelminthic, molluscicidal and in vivo antiplasmodialactivities [15,18].…”

Antimicrobial Homoisoflavonoids from the Rhizomes of Polygonatum verticillatum

“…[1] [2] Homoisoflavonoids are one of such rare and special subclass of flavonoids, that apart from being an effective antimicrobial agent also possess antimutagenic, antioxidant, immunomodulation, antidiabetic, anti-inflammatory, and cytotoxic activities because of their structure diversity. [3] Approximately, 240 natural occurring homoisoflavonoids have been isolated so far from different part of various plants. [4] Polygonatum verticillatum (L.) ALL.…”