CBIOS - Center for Research in Biosciences and Health Technologies, Universidade Lusófona, 1749-024, Lisboa, Portugal.
Research Institute for Medicines (iMed.ULisboa), Faculty of Farmacy, Universidade de Lisboa, 1649-003, Lisboa, Portugal.
Sci Rep. 2024 Jul 23;14(1):16990. doi: 10.1038/s41598-024-67384-0.
Protein kinase C is a family of kinases that play important roles in carcinogenesis. Medicinal plants from Plectranthus spp. (Lamiaceae) are a well-known source of interesting abietanes, such as 7α-acetoxy-6β-hydroxyroyleanone (Roy). This study aimed to extract and isolate Roy from P. grandidentatus Gürke, comparing two extraction methods (CO supercritical and ultrasound-assisted acetonic extraction), and design new royleanone derivatives for PKC modulation focusing on breast cancer therapy. The concentration of Roy in the extracts was determined by HPLC-DAD. The supercritical extraction method yielded 3.6% w/w, with the presence of 42.7 μg mg of Roy (yield of 0.13%), while ultrasound-assisted acetonic extraction yielded 2.3% w/w, with the presence of 55.2 μg mg of Roy (yield of 0.15%). The reactivity of Roy was investigated aiming at synthetizing new ester derivatives through standard benzoylation and esterification reactions. The benzoylated (Roy-12-Bz) and acetylated (Roy-12-Ac) derivatives in the C12 position were consistently prepared with overall good yields (33-86%). These results indicate the 12-OH position as the most reactive for esterification, affording derivatives under mild conditions. The reported di-benzoylated (RoyBz) and di-acetylated (RoyAc) derivatives were also synthesized after increasing the temperature (50 °C), reaction time, and using an excess of reagents. The cytotoxic potential of Roy and its derivatives was assessed against breast cancer cell lines, with RoyBz emerging as the most promising compound. Derivatization at position C-12 did not offer advantages over di-esterification at positions C-12 and C-6 or over the parent compound Roy and the presence of aromatic groups favored cytotoxicity. Evaluation of royleanones as PKC-α, βI, δ, ε, and ζ activators revealed DeRoy's efficacy across all isoforms, while RoyPr showed promising activation of PKC-δ but not PKC-ζ, highlighting the influence of slight structural changes on isoform selectivity. Molecular docking analysis emphasized the importance of microenvironmental factors in isoform specificity, underscoring the complexity of PKC modulation and the need for further exploration.
蛋白激酶 C 是一类激酶，在致癌作用中发挥重要作用。唇形科假糙苏属（Plectranthus spp.）植物是有趣的贝壳杉烷的著名来源，如 7α-乙酰氧基-6β-羟基罗内酯酮（Roy）。本研究旨在从大齿假糙苏（P. grandidentatus Gürke）中提取和分离 Roy，比较两种提取方法（CO 超临界和超声辅助丙酮提取），并设计新的罗内酯酮衍生物以调节蛋白激酶 C，重点用于乳腺癌治疗。通过 HPLC-DAD 测定提取物中 Roy 的浓度。超临界提取法得到 3.6%w/w，罗内酯酮含量为 42.7μg·mg（收率 0.13%），而超声辅助丙酮提取法得到 2.3%w/w，罗内酯酮含量为 55.2μg·mg（收率 0.15%）。研究 Roy 的反应性，旨在通过标准苯甲酰化和酯化反应合成新的酯衍生物。在 C12 位通过标准苯甲酰化和酯化反应成功合成了 Roy-12-Bz 和 Roy-12-Ac 衍生物，产率均较高（33-86%）。这些结果表明 12-OH 位是酯化反应最活跃的位置，在温和条件下得到衍生物。在提高温度（50°C）、延长反应时间和使用过量试剂后，还合成了报道的双苯甲酰化（RoyBz）和双乙酰化（RoyAc）衍生物。评估 Roy 及其衍生物对乳腺癌细胞系的细胞毒性，结果表明 RoyBz 是最有前途的化合物。在 C12 位的酯化反应与在 C12 和 C-6 位的二酯化反应或母体化合物 Roy 相比没有优势，并且芳香族基团的存在有利于细胞毒性。罗内酯酮作为蛋白激酶 C-α、βI、δ、ε 和 ζ 激活剂的评价表明，DeRoy 对所有同工型均有效，而 RoyPr 对蛋白激酶 C-δ有较好的激活作用，但对蛋白激酶 C-ζ 没有作用，这突出了结构细微变化对同工型选择性的影响。分子对接分析强调了微环境因素对同工型特异性的重要性，突出了蛋白激酶 C 调节的复杂性，需要进一步探索。
