Abstract:Ochnaflavone, a naturally occurring biflavonoid composed of two units of apigenin (5,7,4'-trihydroxyflavone) joined via a C-O-C linkage, was first synthesized and evaluated its inhibitory activity on PGE2 production. Total synthesis was accomplished through modified Ullmann diaryl ether formation as a key step. Coupling reactions of 4'-halogenoflavones and 3'-hydroxy-5,7,4'-trimethoxyflavone were explored in diverse reaction conditions. The reaction of 4'-fluoro-5,7-dimethoxyflavone (2c) and 3 '-hydroxy-5,7,… Show more
“…Since the report of its first isolation from the leaves of Ochna squarrosa , ochnaflavone has been isolated from other genus of the Ochnaceae family. Total synthesis has also been achieved . Isolation of 7‐ O ‐methylochnaflavone is mentioned once in the literature where the authors declared that it is a known molecule .…”
The study of the MeOH extract of the leaves of Campylospermum excavatum led to the isolation of a nitrile glucoside, named campyloside C (1) and an original derivative of ochnaflavone, 7-O-methylochnaflavone (2), along with three known biflavonoids, amentoflavone, sequoiaflavone, and sotetsuflavone (3 - 5). The linkage site of the sub-units of 2 was confirmed by chemical correlation, after semi-synthesis of a trimethoxylated derivative of ochnaflavone (2a). The structures of these compounds as well as their relative and absolute configurations were assigned by 1D- and 2D-NMR experiments, HR-ESI-MS and Electronic Circular Dichroism (ECD) calculations. A low-pass J filter HMBC experiment was performed in order to define the configuration of the double bond of 1. All of the biflavonoids were evaluated against protozoan parasites. Amentoflavone moderately inhibited the promastigote form of Leishmania infantum.
“…Since the report of its first isolation from the leaves of Ochna squarrosa , ochnaflavone has been isolated from other genus of the Ochnaceae family. Total synthesis has also been achieved . Isolation of 7‐ O ‐methylochnaflavone is mentioned once in the literature where the authors declared that it is a known molecule .…”
The study of the MeOH extract of the leaves of Campylospermum excavatum led to the isolation of a nitrile glucoside, named campyloside C (1) and an original derivative of ochnaflavone, 7-O-methylochnaflavone (2), along with three known biflavonoids, amentoflavone, sequoiaflavone, and sotetsuflavone (3 - 5). The linkage site of the sub-units of 2 was confirmed by chemical correlation, after semi-synthesis of a trimethoxylated derivative of ochnaflavone (2a). The structures of these compounds as well as their relative and absolute configurations were assigned by 1D- and 2D-NMR experiments, HR-ESI-MS and Electronic Circular Dichroism (ECD) calculations. A low-pass J filter HMBC experiment was performed in order to define the configuration of the double bond of 1. All of the biflavonoids were evaluated against protozoan parasites. Amentoflavone moderately inhibited the promastigote form of Leishmania infantum.
“… Scheme 1 Total synthesis of biflavonoid. Reagents and conditions: a) benzaldehyde, KOH, MeOH, rt, overnight, 70–87%; b) I 2 , DMSO, 100 °C, overnight, 75–86%; and c) Ullmann modified coupling reaction, 8–58% [80] . …”
“…As it is, compound 1 is comprised of -C-O-Cbetween its two flavone moieties, strategically its synthesis may be carried out through the Baker-Venkataraman rearrangement of the corresponding diphenyl ether dialdehyde, followed by flavone nuclei building [18] as illustrated in Scheme 1. Another approach would be building up of the diaryl ether bridge by a simple nucleophilic aromatic substitution reaction, followed by diflavonyl nuclei building as illustrated in Scheme 2 [37].…”
Section: Synthetic Sourcesmentioning
confidence: 99%
“…Synthesis of derivatives of compound 1 focused on the dihydro and/or methoxy substituents, thus, synthesis of 2,3,2'',3''tetrahydroochnaflavone and its methoxy derivative was reported by Yingpeng et al and Ndoile and van-Heerden, respectively [37,39].…”
Section: Scheme 1 Synthesis Of Penta-o-methylochnaflavone [18]mentioning
Aims: To profile and address matters surrounding ochnaflavone (1), derivatives and analogues. Methodology: Papers concerning ochnaflavone, derivatives and analogues were accessed from search engines such as google scholar and pubmed. Results: Ochnaflavone and derivatives are compounds bearing ether linkage between the two Brings of the two flavonoid moieties. These compounds are known to possess potent biological activities such as anti-inflammatory, anticancer, anti HIV and antimicrobial.
Conclusion:In this paper, an overview summary of ochnaflavone, derivatives and analogues from past to present is presented. Thus, the paper provides a sense of focus to researchers; seal breaks the unattended matters, and therefore, spearheads new research areas concerning these compounds.
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