Ceratonia siliqua L. Pod Extract: From Phytochemical Characterization to Liposomal Formulation and Evaluation of Behaviour in Cells

Abstract

The formulation of plant extracts in phospholipid vesicles is a promising strategy to exploit their biological properties while solving problems related to poor solubility in water, high instability, and low skin permeation and retention time. In this study, Ceratonia siliqua ripe pods were used for the preparation of a hydro-ethanolic extract, which showed antioxidant properties owing to the presence of biologically active compounds identified by liquid chromatography–mass spectrometry (e.g., hydroxybenzoic acid and flavonoid derivatives). To improve the applicability of the extract in therapy, a topical formulation based on liposomes was explored. The vesicles were characterized by small size (around 100 nm), negative charge (−13 mV), and high entrapment efficiency (>90%). Furthermore, they displayed both spherical and elongated shapes, with oligolamellar structure. Their biocompatibility was demonstrated in cells, including erythrocytes and representative skin cell lines. The antioxidant activity of the extract was proved by the scavenging of free radicals, the reduction of ferric ions, and the protection of skin cells from oxidative damage.

Biological Activities of Ceratonia siliqua Pod and Seed Extracts: A Comparative Analysis of Two Cretan Cultivars

“…The inferior antioxidant activity following extraction with hexane compared to the 30% aqueous-methanol system, that was observed in the DPPH experiments, was also supported by the intracellular ROS levels. Our results agree with findings in the literature, where pretreatment with C. siliqua pod extract was shown to ameliorate the viability of 3T3 embryonic mouse fibroblasts, immortalized human keratinocytes, and A431 squamous carcinoma cells exposed to H 2 O 2 [37], while an aqueous carob pod extract was found to protect against H 2 O 2 -induced DNA damage [42]. Interestingly, reducing effects of carob extract on intracellular ROS levels have been also reported for human sperm cells [67].…”

“…On the other hand, some of the fractions, i.e., CSE1.2 and CSE2.1 (under serum-free and low-serum conditions), did result in reduced viability; hence, lower noncytotoxic concentrations were chosen for the respective experiments (Table S2). We did not locate any other studies in the literature regarding carob extracts' effects on human skin fibroblasts; however, liposome encapsulated C. siliqua pod extracts tested on 3T3 embryonic mouse fibroblasts, and immortalized human keratinocytes (HaCaT) have been reported to be noncytotoxic [37], in accordance with our findings. There are many studies in the literature regarding carob extracts' cytotoxicity towards a variety of different cancer cell lines [33,[38][39][40][41][42][43][44][45][46][47][48][49][50][51].…”