Superior anti-neoplastic activities of triacontanol-PEG conjugate: synthesis, characterization and biological evaluations

Triacontanol (TA, C30H62O), abundantly present in plant cuticle waxes and bee waxes, has been found to display promising anti-neoplastic potentials. As a long chain fatty alcohol, TA possesses limited aqueous solubility, which hinders its medicinal application. To overcome its solubility barrier, a polymer prodrug was synthesized through attaching TA to poly ethylene glycol (PEG), using succinic acid as a linker with bifunctional amide and ester bonds. Anti-neoplastic effects of PEG-TA were assessed in LoVo and MCF7 cells, anti-proliferative and apoptosis-inducing activities were subsequently confirmed in mouse xenograft model. Encouragingly, PEG-TA possessed selective anti-cancer ability. It did not exhibit significant cytotoxicity on normal cells. Mechanistic examination revealed inhibition of NF-κB nuclear translocation, suppression on matrix degradation enzyme and down-regulation of angiogenic signaling might contribute to its anti-malignant effects. Pharmacokinetics clearly indicated PEGylated TA (named as mPEG2K-SA-TA) substantially enhanced TA delivery with increased plasma exposure (19,791 vs. 336.25 ng·mL-1·h-1, p < .001), mean residence time (8.46 vs. 2.95 h, p < .001) and elimination half-life (7.78 vs. 2.57 h, p < .001) compared to those of original TA. Moreover, mPEG2K-SA-TA appeared to be safe in preliminary toxicological assessment. PEGylated TA also emerged as a functional carrier to deliver hydrophobic chemotherapeutic agents, since it readily self-assembled to micelles in aqueous solution with a low critical micelle concentration (CMC, 19.1 µg·mL-1). Conclusively, PEG-TA conjugate displayed superior anti-neoplastic activities and low toxicity, as well as facilitated the delivery of other hydrophobic agents, which appeared to be an innovative strategy for cancer therapy.

PEGylated Triacontanol Substantially Enhanced the Pharmacokinetics of Triacontanol in Rats

Triacontanol (TA), a natural compound with various health benefits, is extensively used as a nutritional supplement. The therapeutic and nutraceutical applications of TA are limited due to its poor aqueous solubility. PEGylated triacontanol (PEGylated TA) was designed to improve the solubility and pharmacokinetics of TA. After PEGylation, the solubility (∼250 g·L^-1 versus 9 × 10^-14 g·L^-1), body residence (MRT, 9.40 ± 2.03 h versus 2.59 ± 0.705 h, p < 0.001), and systemic exposure (AUC_0-inf, 29.1 ± 5.33 μM·h versus 0.529 ± 0.248 μM·h, p < 0.001) of TA were all significantly increased compared to pristine TA. When intravenously administered (6.85, 22.8, and 68.5 μmol·kg^-1) in rats, PEGylated TA exhibited a slow clearance (44.8 ± 8.62, 47.9 ± 5.18, and 46.9 ± 16.5 mL·h^-1·kg^-1), long elimination half-life (8.76 ± 0.96, 10.4 ± 1.66, and 11.1 ± 2.81 h), and abundant systemic exposure (AUC_{0- t}, 155 ± 24.2, 523 ± 56.2, and 1709 ± 245 μM·h). Meanwhile, its metabolite TA showed a high AUC_{0- t} (28.4 ± 5.14, 151 ± 25.4, and 797 ± 184 μM·h) and slow elimination ( t_1/2, 10.1 ± 2.03, 7.78 ± 1.74, and 6.82 ± 0.58 h). Our results demonstrated that PEGylated TA has superior pharmacokinetics, which enhanced its nutritional and pharmacodynamic potency, and thus warrants further investigations.