Novel Biologically Active Bibenzyls from Bauhinia saccocalyx Pierre

Abstract

Four new bibenzyls, bauhinols A-D (1-4), together with the two known bibenzyls 5 and 6, were isolated from the roots of Bauhinia saccocalyx, and their structures were elucidated by analyses of spectroscopic data. Bauhinol A (1) exhibits significant cytotoxicity towards NCI-H187 (small-cell lung cancer), BC (breast cancer), and KB (oral-cavity cancer) cell lines, with IC50 values of 2.7-4.5 microg/ml. Bauhinol B (2) is cytotoxic against NCI-H187 (IC50 = 1.1 microg/ml) and BC (IC50 = 9.7 microg/ml) cell lines, but inactive toward the KB cell line (at 20 microg/ml). Compound 2 also is mildly antifungal towards Candia albicans (IC50 = 28.9 microg/ml). Bibenzyl 6 is active against NCI-H187 (IC50 = 14.1 microg/ml) and BC (IC50 = 4.0 microg/ml) cells, but inactive (at 20 microg/ml) toward the KB cell line. Compounds 1, 2, and 6 show mild antimycobacterial activities, with MIC values of 25-50 microg/ml, but are inactive at 20 microg/ml against the K1 malarial parasite strain (Plasmodium falciparum). While bauhinol A (1) is inactive against cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2), compounds 2 and 6 inhibit both COX-1 and COX-2, with IC50 values comparable to those of the standard drug, aspirin (Table 3).

Effects of different extracts of Cremastra appendiculata (D. Don) Makino Cremastra appendiculata (D. Don) Makino on apoptosis of A549 cells

“…Bibenzyl compounds are present in the EtAc extract of Cremastra appendiculata (D. Don) Makino [19]. These compounds exerted significant cytotoxicity against small cell lung cancer NCI-H187 cells [20]. It has been reported that the EtAc extract exerted inhibitory effect on LA795 cell line (mouse lung adenocarcinoma cell line, as confirmed using MTT assay).…”

New Cytotoxic Bibenzyl and Other Constituents from Bauhinia ungulata L. (Fabaceae)

“…MeO groups at δ (C) 55.95 (MeO–C(3,5)), 8.19 (Me–C(4)). The presence of the two CH 2 C‐atoms together with twelve C‐atoms in the range of δ (C) 104.21 – 158.48 were used to characterize 1 as a bibenzyl . Comparison of the 1 H‐ and 13 C‐NMR data of 1 with those reported for bauhinol E, a compound isolated from Bauhinia purpurea , showed high similarity, except for the presence of the signal at δ (H) 3.75 ( s , 6 H) observed in the 1 H‐NMR spectrum of 1 , correlated in the HSQC with the signal at δ (C) 55.95 ( Table ), which was assigned to an additional MeO group (MeO–C(3,5)).…”

“…Since bibenzyls are reported to have cytotoxic activities, the new bibenzyl ( 1 ) has been evaluated against HL‐60 (human pro‐myelocytic leukemia), MCF‐7 (human breast adenocarcinoma), NCI‐H292 (human lung carcinoma) and HEP‐2 (human cervical adenocarcinoma) cell lines, using the MTT assay . Doxorubicin was used as the positive control.…”

“…The occurrence of bibenzyls, flavonoids, triterpenoids, and oxepin derivatives is common in Bauhinia species, and the isolation of the bibenzyls 1 and 2 , the flavonoids liquiritigenin ( 3 ), guibourtinidol ( 4 ), fisetinidol ( 5 ), narigenin ( 13 ), and eriodictyol ( 14 ), the triterpenoids taraxerol ( 6 ), betulinic acid ( 7 ), taraxerone ( 8 ), and glutinol ( 9 ), and the oxepinic derivative pacharin ( 12 ) from B . ungulata is in agreement with the chemotaxonomic profile of the genus Bauhinia .…”

Exciting progress in the transition metal‐catalyzed synthesis of oxepines, benzoxepines, dibenzoxepines, and other derivatives

“…These compounds were found to have potential uses in pharmaceuticals [4][5][6] and also in polymers. The number of biological properties of these compounds is containing anti-inflammatory, [7][8][9] antiproliferative, [10] antitumor [1] and anticancer, [10] antiplasmodial, [11] antihelminthic activity, [12] antibiotic activity, [13][14][15][16] antiestrogenic, [17] analgesic, [18] antipsychotic, [9,[19][20][21] angiotensin II receptor antagonistic, [22] antioxidant, [23] antimycobacterial, [24] and antiapoptosis. [25] Some of oxepine, benzoxepine, and dibenzoxepine derivatives have been synthesized by Tishchenko-like reaction, [26] Friedel-Crafts acylation reactions, [27] Suzuki coupling, [28] and Catellani reaction.…”