Roma Pandey, Veena Vishwakarma
Green synthesis of nanoparticles is an emerging area which is environment-friendly and cost-effective with broad range of biomedical applications. In recent years, Aloe vera (L.) Burm.f. has gained significant attention due to its therapeutic potential. The presence of bioactive compounds and easy isolation have provided many opportunities to fabricate nanoparticles using A. vera extracts. It contains several reducing agents (emodin, acemannan, glucomannans) capping agents (aloin, aloesin, emodin) and stabilizing agents (organic acid, acemannan) involved in the synthesis of metal nanoparticles ranging from 3 to 192 nm size. A. vera plant extract has been widely used in preparation of various metal (Ag, Au, Fe, Zn, Cu, Mg, Ti, Ni and Se) nanoparticles. This review has reported working concentrations of nanoparticles ranged 25–780 µg/mL for AgNPs, 20–2000 µg/mL for AuNPs, 5–100 µg/mL for CuNPs, 390–1560 µg/mL for FeNPs, 10 mg/mL for ZnO, 1–5 mg/mL for MgO, and 125–500 µg/mL for NiNPs, across studies evaluating their antimicrobial, antioxidant, catalytic, and anticancer activities. Studies on anticancer activity of A. vera–based NPs in various in vitro (e.g. MCF-7, HeLa, MDA, HT-29, CC1-PI19, SiHa, HNCF-PI52, AMJ13, B16F10 etc.) and in vivo (e.g. Wistar rats) models, which is helpful in formulating nanoparticle-based drug delivery systems, pharmaceuticals, and biosensors are also included. Overall, this review summarizes the latest research progress on the nanofabrication of various metal-based nanoparticles using extracts of A. vera, their characterization, and diverse biomedical applications.