Carob (Ceratonia siliqua) leaves: A comprehensive analysis of bioactive profile and health-promoting potential of an untapped resource

Carob is a resilient plant with ecological and nutritional significance. A comprehensive study of Ceratonia siliqua leaves (CSL) was conducted to explore its chemical composition and health-promoting potential, aiming at improving the carob-crop sustainability through valorization of this untapped co-product. UHPLC-DAD-HRMS/MS quali-quantitative profiling of CSL revealed high levels of n-galloylated glucoses (129-196 mg g-1) and flavonol-glycosides (36-42 mg g-1), with siliquapyranone (39-56 mg g-1), 1,2,3,6-tetragalloylglusose (47-69 mg g-1) and myricitrin (27-33 mg g-1) as main markers. Highest bioactive content and antioxidant capacity (5.0 and 3.1 TEAC) was obtained during pods harvesting. Besides significant antioxidant potential, CSL exhibited strong-high inhibitory activity against α-glucosidase, acetylcholinesterase and butyrylcholinesterase (IC50, 0.51, 13.5 and 58.0 μg mL-1, respectively). 1,2,3,6-tetragalloylglusose and siliquapyranone are the main contributors to antioxidant and α-glucosidase inhibitory capacities. Excellent ability of extract and 1,2,3,6-tetragalloylglusose (IC50, 0.05 μM) in selectively inhibiting α-glucosidase, make them promising candidates to manage hyperglycemia with fewer side effects.

Phytochemical Analysis and Biological Evaluation of Carob Leaf (Ceratonia siliqua L.) Crude Extracts Using NMR and Mass Spectroscopic Techniques

Carob leaves have gained attention for their bioactive properties and traditional medicinal uses, including as treatment for diabetes, digestive disorders, and microbial infections. The aim of this study was to explore the phytochemical composition of carob leaf acetone extracts using advanced spectroscopic techniques. The combined use of heteronuclear nuclear magnetic resonance (NMR) experiments with 1D selective nuclear Overhauser effect spectroscopy (NOESY) offers detailed structural insights and enables the direct identification and quantification of key bioactive constituents in carob leaf extract. In particular, the NMR and mass spectrometry techniques revealed the presence of myricitrin as a predominant flavonoid, as well as a variety of glycosylated derivatives of myricetin and quercetin, in acetone extract. Furthermore, siliquapyranone and related gallotannins are essential constituents of the extract. The potent inhibitory effects of the carob leaf extract on Staphylococcus aureus (MIC = 50 μg mL-1) and a-glucosidase enzyme (IC50 = 67.5 ± 2.4 μg mL-1) were also evaluated. Finally, the antibacterial potency of carob leaf constituents were calculated in silico; digalloyl-parasorboside and gallic acid 4-O-glucoside exert a stronger bactericidal activity than the well-known myricitrin and related flavonoids. In summary, our findings provide valuable insights into the bioactive composition and health-promoting properties of carob leaves and highlight their potential for pharmaceutical and nutraceutical applications.

Carob Seeds as a Source of Bioactive Flavonoid Derivatives: Isolation, Network Pharmacology-guided Anti-cancer Activity, and HPLC Standardization

Carob, Ceratonia siliqua L. (CS), is a legume well-known for its edible pod pulp. Its seeds are used almost exclusively as a source of the food additive E410. Although a variety of metabolites have been identified by HPLC and LC-MS analysis in CS, reports concerned with their isolation are scarce. In this study, two flavonoid derivatives were isolated from the methanolic extract of CS seeds, namely, quercetin-3-O-rhamnoside and 4'-p-hydroxybenzoylisorhamnetin-3,7-di-O-rhamnoside. Network pharmacology was unusually used as a guide for estimation of the biological potential of the isolated compounds. Finally, the methanolic extract of CS seeds and its ethyl acetate fraction were standardized for their 4'-p-hydroxybenzoylisorhamnetin-3,7-di-O-rhamnoside content by HPLC. The identified isolates displayed the ability to interfere with the activity of several target proteins associated with renal and colon cancers. Their cytotoxic effect on renal and colorectal cancer cell lines was investigated in comparison to Doxorubicin. The selectivity of the isolated compounds was evaluated on normal human fetal fibroblast cell lines. The isolated 4'-p-hydroxybenzoylisorhamnetin-3,7-di-O-rhamnoside showed very potent cytotoxic activity against the tested cell lines with the highest selectivity. CS seeds can be used as a source of bioactive flavonoid derivatives that can be incorporated in pharmaceutical industries.

Carob extract induces spermatogenesis in an infertile mouse model via upregulation of Prm1, Plzf, Bcl-6b, Dazl, Ngn3, Stra8, and Smc1b

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnopharmacological studies for drug discovery from natural compounds play an important role for developing current therapeutical platforms. Plants are a group of natural sources which have been served as the basis in the treatment of many diseases for centuries. In this regard, Ceratonia siliqua (carob) is one of the herbal medicine which is traditionally used for male infertility treatments. But so far the main mechanisms for effects of carob are unknown. Here, we intend to investigate the ability of carob extract to induce spermatogenesis in an azoospermia mouse model and determine the mechanisms that underlie its function.

AIM OF THE STUDY

This is a pre-clinical animal model study to evaluate the effect of carob extract in spermatogenesis recovery.

METHODS

We established an infertile mouse model with the intent to examine the ability of carob extract as a potential herbal medicine for restoration of male fertility. Sperm parameters, as well as gene expression dynamics and levels of spermatogenesis hormones, were evaluated 35 days after carob administration.

RESULTS

Significant enhanced sperm parameters (P < 0.05) showed that the carob extract could induce spermatogenesis in the infertile mouse model. Our data suggested an anti-apototic and inducer role in the expressions of cell cycle regulating genes. Carob extract improved the spermatogenesis niche by considerable affecting Sertoli and Leydig cells (P < 0.05). The carob-treated mice were fertile and contributed to healthy offspring that matured. Our data confirmed that this extract triggered the hormonal system, the spermatogenesis-related gene expression network, and signaling pathways to induce and promote sperm production with notable level (P < 0.05). We found that the aqueous extract consisted of a polar and mainly well water-soluble substance. Carob extract might upregulate spermatogenesis hormones via its amino acid components, which were detected in the extract by liquid chromatography-mass spectrometry (LC-MS).

CONCLUSION

Our results strongly suggest that carob extract might be a promising future treatment option for male infertility. This finding could pave the way for clinical trials in infertile men. This is the first study that has provided reliable, strong pre-clinical evidence for carob extract as an effective candidate for fertility recovery in cancer-related azoospermia.

Use of Chemometrics for Correlating Carobs Nutritional Compositional Values with Geographic Origin

Carobs unique compositional and biological synthesis enables their characterization as functional foods. In the present study, 76 samples derived from fruit and seeds of carobs, with origin from the countries of the Mediterranean region (Cyprus, Greece, Italy, Spain, Turkey, Jordan and Palestine) were analyzed for their nutritional composition, in order to identify potential markers for their provenance and address the carobs' authenticity issue. Moisture, ash, fat, proteins, sugars (fructose, glucose, sucrose), dietary fibers and minerals (Ca, K, Mg, Na, P, Cu, Fe, Mn, Zn) were estimated following official methods. Due to the large number of data (76 samples × 17 parameters × 7 countries), chemometric techniques were employed to process them and extract conclusions. The samples of different geographical origin were discriminated with 79% success in total. The carobs from Cyprus, Italy and Spain were correctly classified without error. The main discriminators were found to be the dietary fibers, the carbohydrates and Cu, Zn and Mn, which emphasize their specific nutritional added value to the product and the country of origin impact. The results suggest that the proposed analytical approach is a powerful tool that enables the discrimination of carobs based on their country of origin. This research contributes to authenticity of carobs, adding value to local products.

Assessing the volatile profile of carob tree (Ceratonia siliqua L.)

Biogenic volatile organic compounds (VOCs) contribute to the communication, growth, breeding, and defense of plant; their role in plant kingdom is vital. Carob tree is cultivated mainly in Middle East and eastern European countries (e.g., Spain, Italy, Greece, Cyprus) and lately in Australia, the USA, and South Africa. Therefore, it is examined as a case study for its volatile emissions in the environment. Apart from the VOCs emitted from carob flowers and fruit, carob is considered of great interest for the food industry (carob powder), not only for its health benefits but also due to its characteristic strong aroma, which can be maintained even after processing (roasting). Solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) analyses of carob flowers, fruit, and powder (commercial samples) were performed and the detected VOCs are presented and discussed. The most prominent chemical classes emitted from carob fruit and powder appeared to be acids followed by esters and aldehydes/ketones, whereas from carob flowers the terpenoids. The strongest VOCs both in carob fruits and powder were propanoic acid, 2-methyl (isobutyric acid) and in flowers ethanol. The uniqueness of carob benefits is well known in the agriculture, pharmaceutical, cosmetic, and food sector and is closely related to the agro-economy and long history of eastern Mediterranean countries.