Effects of seven pure flavonoids from mosses on germination and growth of Tortula muralis HEDW (Bryophyta) and Raphanus sativus L (Magnoliophyta)

Dried mosses (five moss species) were progressively extracted and subjected to a four-step Craig distribution. Seven pure flavonoids were isolated and identified. The flavonoids were the flavones apigenin, apigenin-7-O-triglycoside, lucenin-2, luteolin-7-O-neohesperidoside, saponarine and vitexin; and the biflavonoid bartramiaflavone and they were submitted to biological tests. The tests were performed in vitro on spore germination and protonemal growth of the moss Tortula muralis and on seed germination and root growth of Raphanus sativus. Flavonoids caused a decrease in the percentage of spore germination, protonemal development and root growth. In addition they caused morphological alterations, such as forked tips, swollen apices, rounded cells and early formation of brood cells in the protonemata. Data were discussed in relation to the presence of allelochemicals in mosses.     

Biflavonoids from Araucaria angustifolia protect against DNA UV-induced damage

Ultraviolet radiation is one of the most deleterious forms of radiation to terrestrial organisms and is involved in formation of mutagenic pyrimidine dimers and oxidized nucleotides. The biflavonoid fraction (BFF), extracted from needles of Araucaria angustifolia was capable of protecting calf thymus DNA from damage induced by UV radiation. This occurred through prevention of cyclobutane thymine dimer and 8-oxo-7,8-dihydro-2′-deoxyguanosine formation, this being quantified by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) in a multiple reaction monitoring mode (MRM) and by HPLC-coulometric detection, respectively.     

Biflavonoids from Brazilian pine Araucaria angustifolia as potentials protective agents against DNA damage and lipoperoxidation

A biflavonoid fraction (BFF) obtained from Araucaria angustifolia needles was effective to quench singlet oxygen (1O2), to protect plasmid DNA against single strand break (ssb) caused by 1O2 or Fenton reaction and to inhibit Fenton or UV radiation-induced lipoperoxidation in phosphatidylcholine liposomes. The activity of the biflavonoid fraction (BFF) was compared with quercetin, rutin (flavonoids), ginkgetin, amentoflavone (biflavonoids), alpha-tocopherol and Trolox. The BFF displayed a higher quenching rate constant compared to flavonoids and biflavonoids and protected against ssb induced by 1O2. Although the BFF was not as efficient as either flavonoids, alpha-tocopherol or Trolox in protection against ssb induced by Fenton-reaction or lipoperoxidation, these scavenging properties suggest that BFF is still an excellent candidate for successful employment as an antioxidant and photoprotector.     

Two biflavonoids from Ouratea flava stem bark

In a chemical investigation on the stem bark of Ouratea flava, two biflavonoids: 1-[3-(2,4-dihydroxy-benzoyl)-4,5,6-trihydroxy-2-(4-hydroxy-phenyl)-benzofuran-7-yl] -3-(4-hydroxy-phenyl) -propenone (flavumone A) and 3-(2,4-dihydroxy-benzoyl)-4-hydroxy-2,7-bis-(4-hydroxy-phenyl) -7,8- dihydro-furo[2,3-f]chromen-9-on (flavumone B) were isolated along with five known flavonoids. Their structures were established by various analyses including 2D-NMR spectroscopy.     

Nematicidal activity against Aphelenchoides besseyi and Ditylenchus destructor of three biflavonoids,isolated from roots of Stellera chamaejasme

Aphelenchoides besseyi and Ditylenchus destructor can cause serious problems for a number of important agricultural crops and vegetables. In this study, the ethanol extract of Stellera chamaejasme L. roots showed strong nematicidal activity against Aphelenchoides besseyi and Ditylenchus destructor. By using a bioactivity-driven fractionation, three biflavonoids were isolated from the extract and their structures were identified by mass and nuclear magnetic resonance spectral data. Nematicidal activity bioassays revealed that isoneochamaejasmin A had the strongest nematicidal activity against A. besseyi and D. destructor with LC₅₀ values of 2.32 and 0.18?mM at 72?h, respectively. Chamaejasmenin B displayed weaker nematicidal activity against A. besseyi with an LC₅₀ value of 3.94?mM at 72?h. Neochamaejasmin B induced the lowest mortality against D. destructor with an LC₅₀ values of 15.6?mM at 72?h. These results suggested that the kind and position of substitutions and the relative configuration of 2-H/3-H and 2”-H/3”-H could be considered as important factors responsible for the nematicidal activity of these purified C-3/C-3″ biflavonoids.     

The Chemical Constituents from Podocarpus brevifolius

Ten compounds were isolated from the barks and leaves of Podocarpus brevifolius (Podocarpaceae) for the first time. They are identified as isokaurene (1), △9- isoclextropimaric acid (2), isoginkgetin (3), sciadopitysin (4), amentoflavone-4′,4″′, 7, 7″-tetramethylether (5), sequoyitol (6), β-sitosterol (7), daucosterol (8), β-sitosterone (9), and 3β, 6β-dihydroxy-stigmast-4-ene (10) by means of spectral analysis, comparison of physio-chemical data and throgh chemical method.     

Eight new biflavonoids with lavandulyl units from the roots of Sophora flavescens and their inhibitory effect on PTP1B

In the course of studying the components from the roots of Sophora flavescens, eight new unusual biflavonoids consisting of a flavanone fused with a dihydrochalcone skeleton were isolated. These new chemical structures were elucidated by means of UV, IR, HRESIMS, NMR and ECD spectroscopic data and a comparison of experimental ECD spectra with calculated ECD spectra. Some compounds were subjected to an antidiabetic bioassay on human recombinant PTP1B inhibition, and showed strong inhibitory activity.