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Abstract Background The successful launch of icaritin, a therapeutic drug for liver cancer derived from Epimedium brevicornu, has provided new impetus for the development of prenylated flavonoids in the field of oncology. Flemingia macrophylla is reported to contain characteristic prenylated flavonoids which can regulate the p53 protein. We aimed to isolate these constituents and conduct activity evaluation, structure–activity relationship, and mechanism studies to provide candidate compounds for antitumor drug development. Methods In this study, chromatographic techniques combined with spectroscopic methods were used to separate, purify, and identify the constituents of Flemingia macrophylla methanol extract. The cytotoxic activity of the constituents was evaluated using an MTT assay with A549 and H1975 cells as the model. The binding mechanism between the compounds and the p53 protein was investigated with molecular docking and validated with cellular thermal shift assay (CETSA). Western blotting (WB) was employed to detect the expression of p53 protein and apoptosis-related proteins in cells. Results Chiral HPLC separation of racemates 1 and 7 provided two pairs of undescribed enantiomers (1a/1b and 7a/7b), along with eight known compounds (2 − 9) isolated from Flemingia macrophylla roots. Their structures were elucidated by spectroscopic analysis, and the absolute configurations of the enantiomers were determined from experimental and calculated electronic circular dichroism data. Compounds 1 − 7, and the non-prenyl analogues 10 − 13, were evaluated for cytotoxic activity against the human lung cancer A549 and H1975 cell line. Compounds 5 − 7 displayed better cytotoxicity than the positive control icaritin in A549 and H1975, with IC50 values ranging from 4.50 to 19.83 μmol·L-1 and

Rootstocks play a vital role in regulating the environmental adaptability and controlling the growth and development of apple trees. M9T337, an excellent apple rootstock widely used in commercial orchards, could confer dwarf tree architectures, early fruiting and suitability for high-density planting. However, the rooting ability of M9T3337 is low when it is vegetatively propagated, and researchers have not yet established an efficient micropropagation system. The present study systematically evaluated the multiplication in adventitious shoots and the in vitro formation of adventitious roots to determine the effects of the culture media and plant growth regulators of M9T337 and a rapid micropropagation system was developed. For the shoot multiplication, the highest multiplication index of 3.93 was obtained on Murashige and Skoog (MS) media supplemented with 2.0 mg/L 6-BA, 0.1 mg/L NAA and 0.3 mg/L GA3 from 12 combinations of 6-BA and NAA. Stronger and taller adventitious shoots were grown on MS supplemented with 1.8 mg/L 6-BA and 0.5 mg/L NAA. The optimal media with 100% rooting was obtained using 1/2 MS supplemented with 0.3 mg/L IBA or MS supplemented with 0.6 mg/L IBA for the rooting induction, resulting in mean rooting numbers of 13.00 and 11.33, respectively. Additionally, the effect on rooting of adding 0.3 mg/L IBA or not on the 1/2 MS and MS media was compared; the results suggested that an appropriate IBA concentration was the key to successful rooting. The rooted plantlets were acclimatised in a shaded greenhouse with an 84% survival rate. The established micropropagation system could be used for the rapid propagation of M9T337 for commercial production.

Adventitious root (AR) formation is indispensable for vegetative asexual propagation. Indole-3-butyric acid (IBA) functioned indirectly as precursor of IAA in regulating AR formation. Ethylene affects auxin synthesis, transport, and/or signaling processes. However, the interactions between auxin and ethylene that control AR formation in apple have not been elucidated. In this study, we investigated the effects of IBA and its interaction with ethylene on AR development in apple. The results revealed that IBA stimulated the formation of root primordia, increased the number of ARs, and upregulated expression of genes (MdWOX11, MdLBD16, and MdLBD29) involved in AR formation. Comparison of different periods of IBA application indicated that IBA was necessary for root primordium formation, while long time IBA treatment obviously inhibited root elongation. RNA-seq analysis revealed that many plant hormone metabolism and signal transduction related genes were differentially expressed. IBA stimulated the production of ethylene during AR formation. Auxin inhibiting ARs elongation depended on ethylene. Together, our results suggest that the inhibitory role of auxin on AR elongation in apples is partially mediated by stimulated ethylene production.