Molecular mechanisms and associated cell signalling pathways underlying the anticancer properties of phytochemical compounds from Aloe species (Review).

Naturally occurring components from various species of Aloe have been used as traditional folk medicine since the ancient times. Over the last few decades, the therapeutic effects of extracts and phytochemical compounds obtained from Aloe vera have been proven in preclinical and clinical studies. Recently, compounds from other Aloe species apart from Aloe vera have been investigated for the treatment of different diseases, with a particular focus on cancer. In the present review, the effects of phytochemical compounds obtained from different Aloe species are discussed, with a specific focus on the effects on cell signalling in cancer and normal cells, and their selectivity and efficacy. This information will be useful for the application of Aloe-derived compounds as therapeutic agents, either alone or in combination with other standard drugs for cancer treatment.

Anticancer Potential of Sutherlandia frutescens and Xysmalobium undulatum in LS180 Colorectal Cancer Mini-Tumors.

Colorectal cancer remains to be one of the leading causes of death worldwide, with millions of patients diagnosed each year. Although chemotherapeutic drugs are routinely used to treat cancer, these treatments have severe side effects. As a result, the use of herbal medicines has gained increasing popularity as a treatment for cancer. In this study, two South African medicinal plants widely used to treat various diseases, Sutherlandia frutescens and Xysmalobium undulatum, were evaluated for potential activity against colorectal cancer. This potential activity for the treatment of colorectal cancer was assessed relative to the known chemotherapeutic drug, paclitaxel. The cytotoxic activity was considered in an advanced three-dimensional (3D) sodium alginate encapsulated LS180 colorectal cancer functional spheroid model, cultured in clinostat-based rotating bioreactors. The LS180 cell mini-tumors were treated for 96 h with two concentrations of each of the crude aqueous extracts or paclitaxel. S. frutescens extract markedly decreased the soluble protein content, while decreasing ATP and AK per protein content to below detectable limits after only 24 h exposure. X. undulatum extract also decreased the soluble protein content, cell viability, and glucose consumption. The results suggested that the two phytomedicines have potential to become a source of new treatments against colorectal cancer.

Capsaicin and Piperine as Functional Excipients for Improved Drug Delivery across Nasal Epithelial Models.

The fruit from various pepper plants has been employed for the seasoning of food, as perfuming agents, and also as traditional medicines. Phytochemicals isolated from different pepper species have been found to modulate the pharmacokinetics of orally administered drugs. This study investigated the possibility to apply capsaicin and piperine (extracted alkaloids) as modulators for drug delivery across the nasal epithelium. Both a nasal epithelial cell line (RPMI 2650) and excised sheep nasal tissue were used as models to investigate the effects of the selected pepper compounds on drug permeation. FITC-dextran 4400 (MW 4400 Da) was used as a large molecular weight marker compound for paracellular transport, while rhodamine 123 was used as a marker compound that is a substrate for P-glycoprotein-mediated efflux. From the permeation results, it was clear that capsaicin inhibited P-glycoprotein efflux to a larger extent, while piperine showed drug permeation enhancement via other mechanisms. The cell cytotoxicity studies indicated that capsaicin was noncytotoxic up to a concentration of 200 µM and piperine up to a concentration of 500 µM as indicated by cell viability above 80%. The histological analysis of the excised nasal tissue and cultured RPMI 2650 cell layers indicated that some damage occurred after treatment with 200 µM capsaicin, but no changes were observed for piperine up to a concentration of 50 µM.

Treatment of Skin Disorders with Aloe Materials.

The skin is the largest organ and functions as a barrier to protect the underlying tissues against the elements and pathogens, while also fulfilling many physiological roles and biochemical functions such as preventing excessive water loss. Skin disorders vary greatly in terms of origin, severity, symptoms and affect persons of all ages. Many plants have been used for medicinal purposes since ancient times including the treatment of skin disorders and diseases. Aloe represents one of the earliest medicinal plant species mentioned in antique scriptures and even in rock art dating back thousands of years. Different Aloe species and materials have been used in the prevention and treatment of skin related disorders. Aloe vera is the most commonly used Aloe species for medicinal purposes. Some of the most prominent skin related applications and disorders that Aloe materials have been investigated for are discussed in this paper, which include cosmetic, radiation, cancer, wound and antimicrobial applications. Both in vitro and in vivo studies are included in the discussions of this paper and comprehensive summaries of all these studies are given in tables in each section. Although some contradictory results were obtained among studies, certain Aloe materials have shown excellent efficacy and exhibited potential for the treatment of skin related disorders and cosmetic applications.