In vitro photo-induced cytotoxic activity of Citrus bergamia and C. medica L. cv. Diamante peel essential oils and identified active coumarins

Cnidii Fructus: A traditional Chinese medicine herb and source of antiosteoporotic drugs

BACKGROUND

Osteoporosis (OP) is a prevalent chronic metabolic bone disease for which limited countermeasures are available. Cnidii Fructus (CF), primarily derived from Cnidium monnieri (L.) Cusson., has been tested in clinical trials of traditional Chinese medicine for the management of OP. Accumulating preclinical studies indicate that CF may be used against OP.

MATERIALS AND METHODS

Comprehensive documentation and analysis were conducted to retrieve CF studies related to its main phytochemical components as well as its pharmacokinetics, safety and pharmacological properties. We also retrieved information on the mode of action of CF and, in particular, preclinical and clinical studies related to bone remodeling. This search was performed from the inception of databases up to the end of 2022 and included PubMed, China National Knowledge Infrastructure, the National Science and Technology Library, the China Science and Technology Journal Database, Weipu, Wanfang, the Web of Science and the China National Patent Database.

RESULTS

CF contains a wide range of natural active compounds, including osthole, bergapten, imperatorin and xanthotoxin, which may underlie its beneficial effects on improving bone metabolism and quality. CF action appears to be mediated via multiple processes, including the osteoprotegerin (OPG)/receptor activator of nuclear factor-κB ligand (RANKL)/receptor activator of nuclear factor-κB (RANK), Wnt/β-catenin and bone morphogenetic protein (BMP)/Smad signaling pathways.

CONCLUSION

CF and its ingredients may provide novel compounds for developing anti-OP drugs.

A comprehensive review of the classical prescription Yiguan Jian: Phytochemistry, quality control, clinical applications, pharmacology, and safety profile

ETHNOPHARMACOLOGICAL RELEVANCE

Yiguan Jian (YGJ) is a classical prescription, which employs 6 kinds of medicinal herbs including Rehmanniae Radix, Lycii Fructus, Angelicae sinensis Radix, Glehniae Radix, Ophiopogonis Radix, and Toosendan Fructus. YGJ decoction is originally prescribed in Qing Dynasty (1636 CE ∼ 1912 CE) in China, and is commonly used to treat liver diseases. There remain abundant literature investigating YGJ decoction from multiple aspects, but few reviews summarized the research and gave a precise definition, which impedes further applications and commercialization of YGJ decoction.

AIM OF THE REVIEW

The aim of this review is to provide comprehensive descriptions of YGJ decoction, tackling with issues in the research and development of YGJ decoction.

MATERIALS AND METHODS

The literature and clinical reports were obtained from the databases including Web of Science, Science Direct, PubMed, Google Scholar, China National Knowledge Infrastructure, China Science Periodical Database, China Science and Technology Journal Database, and SinoMed since 2000. The phytochemical characteristics, quality control, pharmaceutical forms, clinical position, pharmacological effects, and toxic events of YGJ decoction were included for analysis.

RESULT

This review firstly summarized the progress of the chemical existences of YGJ decoction and discussed the advanced methods in monitoring quality of YGJ decoction and its herbal ingredients, particularly in the form of granules. Whilst this review aims to identify the pharmacological actions and clinical impacts of YGJ decoction, the medicinal materials that could provide these benefits were observed in the remaining herbs to exert the anti-fibrotic effects, anti-inflammatory activities, anti-cancer, and anti-diabetic effects, and to universally treat liver and gastric diseases. This review provided supplementary descriptions on the safety issues, especially in Glehniae Radix and Toosendan Fructus, to define the alterations between hepatoprotective activities and unclear toxics in YGJ decoction application.

CONCLUSIONS

Our comprehensively organized review discussed the chemical characteristics and the research in altering or identifying these essences. The effects of YGJ decoction on the non-clinical and clinical tests exert the good management of sophisticated diseases. In this review, current issues are discussed to inform and inspire subsequent research of YGJ decoction and other classical prescriptions.

Anticancer effect of terpenes: focus on malignant melanoma

Melanoma is a highly aggressive and life-threatening form of skin cancer that accounts for a significant proportion of cancer-related deaths worldwide. Although conventional cancer therapies, such as surgical excision, chemotherapy, and radiation, have been used to treat malignant melanoma, their efficacy is often limited due to the development of resistance and adverse side effects. Therefore, there is a growing interest in developing alternative treatment options for melanoma that are more effective and less toxic. Terpenes, a diverse group of naturally occurring compounds of plant origin, have emerged as potential anticancer agents due to their ability to inhibit tumor growth and induce apoptosis in cancer cells. In this review, the current understanding of the anticancer effects of terpenes (including, thymoquinone, β-elemene, carvacrol, limonene, α-pinene, β-caryophyllene, perillyl alcohol, taxol, betulinic acid, α-bisabolol, ursolic acid, linalool, lupeol, and artesunate) was summarized, with a special focus on their potential as therapeutic agents for malignant melanoma.

Citrus Essential Oils: A Rational View on its Chemical Profiles, Mode of Action of Anticancer Effects/Antiproliferative Activity on Various Human Cancer Cell Lines

Cancer is a complex genetic disorder due to uncontrolled growth of abnormal cells in the body, causes damage to the immune system, and may lead to life-threatening situations. Common approaches to cancer treatment includes chemotherapy, hormone therapy, immunotherapy, radiation therapy etc. Development of novel and natural chemotherapeutic agents is highly demanded because of the side effects of synthetic drugs. Essential oils from aromatic plants exhibited antioxidant, antimutagenic, antiproliferative and immunomodulating activities. Mechanism of multidrug resistance and synergistic action of these volatile constituents are responsible for their chemopreventive properties. These oils primarily comprising of terpenoid constituents and are characterized by volatility, aroma, low molecular weight etc. The chemical composition of these oils varies depending on the environmental condition, species, plant part and geographical region. Literature analysis revealed that plant essential oils play an important role in cancer prevention and treatment. Cancer patients exposed to essential oils via inhaler devices were found to have less anxiety, stress, and nausea and insomnia. Nowadays, there is an increasing demand for investigating the biological properties of aromatic plants due to their availability, chemical diversity, and low toxicity. In aromatherapy, Citrus essential oils repress cancer related pain and enhance immune system. Current review summarizes existing variability of the chemical composition of Citrus essential oils and its molecular level anticancer mechanism against various human cancer cell lines. Citrus essential oils enhance cytotoxicity, antiproliferative and apoptotic behavior of cancer cell lines. Since essential oils exhibiting significant anticancer potential is worthy of further investigation for cancer chemoprevention. The findings of various research activities can be exploited by cancer researchers world wide for the development of anticancer drugs which can relieve cancer symptoms.

Authentication of Citrus spp. Cold-Pressed Essential Oils by Their Oxygenated Heterocyclic Components

Citrus essential oils are routinely adulterated because of the lack of regulations or reliable authentication methods. Unfortunately, the relatively simple chemical makeup and the tremendous price variations among Citrus varieties encouraged the interspecies adulteration of citrus oils. In this study, a sensitive UPLC-MS/MS method for the quantitation of 14 coumarins and furanocoumarins is developed and validated. This method was applied to screen the essential oils of 12 different Citrus species. This study, to our knowledge, represents the most comprehensive investigation of coumarin and furanocoumarin profiles across commercial-scale Citrus oils to date. Results show that the lowest amount was detected in calamansi oil. Expressed oil of Italian bergamot showed the highest furanocoumarin content and the highest level of any individual furanocoumarin (bergamottin). Notable differences were observed in the coumarin and furanocoumarin levels among oils of different crop varieties and origins within the same species. Potential correlations were observed between bergapten and xanthotoxin which matches with known biosynthetic pathways. We found patterns in furanocoumarin profiles that line up with known variations among the Citrus ancestral taxa. However, contrary to the literature, we also detected xanthotoxin in sweet orange and members of the mandarin taxon. Using multivariate analysis, we were able to divide the Citrus oils into 5 main groups and correlate them to the coumarin compositions.

Some Natural Photosensitizers and Their Medicinal Properties for Use in Photodynamic Therapy

Despite significant advances in early diagnosis and treatment, cancer is one of the leading causes of death. Photodynamic therapy (PDT) is a therapy for the treatment of many diseases, including cancer. This therapy uses a combination of a photosensitizer (PS), light irradiation of appropriate length and molecular oxygen. The photodynamic effect kills cancer cells through apoptosis, necrosis, or autophagy of tumor cells. PDT is a promising approach for eliminating various cancers but is not yet as widely applied in therapy as conventional chemotherapy. Currently, natural compounds with photosensitizing properties are being discovered and identified. A reduced toxicity to healthy tissues and a lower incidence of side effects inspires scientists to seek natural PS for PDT. In this review, several groups of compounds with photoactive properties are presented. The use of natural products has been shown to be a fruitful approach in the discovery of novel pharmaceuticals. This review focused on the anticancer activity of furanocoumarins, polyacetylenes, thiophenes, tolyporphins, curcumins, alkaloid and anthraquinones in relation to the light-absorbing properties. Attention will be paid to their phototoxic and anti-cancer effects on various types of cancer.

In Vitro Assessment of the Cytotoxic and Antiproliferative Profile of Natural Preparations Containing Bergamot, Orange and Clove Essential Oils

Medicinal plants and essential oils (EOs), in particular, were intensively studied in recent years as viable alternatives for antiproliferative chemical synthetic agents. In the same lines, the present study focuses on investigating the effects of natural preparations (emulsions) based on EOs obtained from Citrus bergamia Risso (bergamot-BEO), Citrus sinensis Osbeck (orange-OEO), and Syzygium aromaticum Merill et L. M. Perry (clove-CEO) on different healthy (human immortalized keratinocytes—HaCaT and primary human gingival fibroblasts—HGF) and human tumor cell lines (human melanoma—A375 and oral squamous carcinoma—SCC-4) in terms of the cells’ viability and cellular morphology. The obtained results indicate that the CEO emulsion (ECEO) induced a dose-dependent cytotoxic in both healthy (HaCaT and HGF) and tumor (A375 and SCC-4) cells. OEO emulsion (EOEO) increased cell viability percentage both for HaCaT and A375 cells and had an antiproliferative effect at the highest concentration in HGF and SCC-4 cells. BEO emulsion (EBEO) decreased the viability percentage of SCC-4 tumor cells. By associating OEO with CEO as a binary mixture in an emulsified formulation, the inhibition of tumor cell viability increases. The E(BEO/OEO) binary emulsion induced an antiproliferative effect on oral health and tumor cells, with a minimal effect on skin cells. The non-invasive tests performed to verify the safety of the test compound’s emulsions at skin level indicated that these compounds do not significantly modify the physiological skin parameters and can be considered safe for human skin.

Bergapten: A review of its pharmacology, pharmacokinetics, and toxicity

Bergapten is a natural furocoumarin, also known as 5-methoxypsoralen, and its medicinal value has been paid more and more attention. By sorting out the pharmacological literature of bergapten, we found that bergapten has a wide range of pharmacological effects, including neuroprotection, organ protection, anticancer, antiinflammatory, antimicrobial, and antidiabetes effects. However，bergapten has complex impacts on the hepatic metabolic enzyme. Moreover, pharmacokinetic studies showed that bergapten has higher absolute bioavailability and can cross the blood-brain barrier and has a great potential for treating brain disease, but the mechanism needs further clarification to make greater use of its ability to treat brain diseases. Furthermore, the phototoxicity of bergapten combined with ultraviolet light has always been mentioned. In view of its wide range of pharmacological activities, bergapten is expected to be a potential drug candidate for the treatment of diabetes and diabetes-induced osteoporosis, epilepsy, Alzheimer's disease, depression, and cancer. However, further studies are needed to elucidate its molecular mechanisms and targets. The phototoxicity of bergapten as a side effect should be further avoided. On the other hand, the photoactivation of bergapten in the anticancer aspect can be better utilized.

Does the chemistry of fungal pigments demand the existence of photoactivated defense strategies in basidiomycetes?

The well-known photosensitizers hypericin, harmane, and emodin are typical pigments of certain mushroom species-is this a coincidence or an indication towards a photoactivated defense mechanism in the phylum Basidiomycota? This perspective article explores this hypothesis by cross-linking the chemistry of fungal pigments with structural requirements from known photosensitizers and insights from photoactivated strategies in the kingdom Plantae. Thereby, light is shed on a yet unexplored playground dealing with ecological questions, photopharmaceutical opportunities, and biotechnological potentials.

Exploring the Potential of Aromatherapy as an Adjuvant Therapy in Cancer and its Complications: A Comprehensive Update

BACKGROUND

Aromatherapy is a traditional practice of employing essential oils for the therapeutic purposes, currently headed under the category of complementary and adjuvant medicine.

OBJECTIVE

The aim of this review article is to summarize the potential health benefits of aromatic essential oil from traditional times till the present. It also proposed some mechanisms which can be utilized as basis for using aromatherapy in cancer and cancer linked complications.

METHODS

To find out the relevant and authentic data, several search engines like Science direct, Pubmed, research gate, etc. were thoroughly checked by inserting key words like aromatherapy, complementary, adjuvant therapy etc. to collect the relevant material in context of article. Also, the chemical components of essential oil were classified based on the presence of functional groups, which are further explored for their cytotoxic potential.

RESULTS

The result depicted the anti-cancer potential of chemical constituents of essential oil against different types of cancer. Moreover, the essential oils show promising anti-inflammatory, anti-microbial, anti-oxidant and anti-mutagenic potential in several studies, which collectively can form the basis for initiation of its anti-cancer utility.

CONCLUSION

Aromatherapy can serve as adjuvant economic therapy in cancer after the standardization of protocol.

Essential Oils and Their Main Chemical Components: The Past 20 Years of Preclinical Studies in Melanoma

Simple Summary

In the last years, targeted therapy and immunotherapy modified the landscape for metastatic melanoma treatment. These therapeutic approaches led to an impressive improvement in patients overall survival. Unfortunately, the emergence of drug resistance and side effects occurring during therapy strongly limit the long-term efficacy of such treatments. Several preclinical studies demonstrate the efficacy of essential oils as antitumoral agents, and clinical trials support their use to reduce side effects emerging during therapy. In this review we have summarized studies describing the molecular mechanism through which essential oils induce in vitro and in vivo cell death in melanoma models. We also pointed to clinical trials investigating the use of essential oils in reducing the side effects experienced by cancer patients or those undergoing anticancer therapy. From this review emerged that further studies are necessary to validate the effectiveness of essential oils for the management of melanoma.

Abstract

The last two decades have seen the development of effective therapies, which have saved the lives of a large number of melanoma patients. However, therapeutic options are still limited for patients without BRAF mutations or in relapse from current treatments, and severe side effects often occur during therapy. Thus, additional insights to improve treatment efficacy with the aim to decrease the likelihood of chemoresistance, as well as reducing side effects of current therapies, are required. Natural products offer great opportunities for the discovery of antineoplastic drugs, and still represent a useful source of novel molecules. Among them, essential oils, representing the volatile fraction of aromatic plants, are always being actively investigated by several research groups and show promising biological activities for their use as complementary or alternative medicine for several diseases, including cancer. In this review, we focused on studies reporting the mechanism through which essential oils exert antitumor action in preclinical wild type or mutant BRAF melanoma models. We also discussed the latest use of essential oils in improving cancer patients’ quality of life. As evidenced by the many studies listed in this review, through their effect on apoptosis and tumor progression-associated properties, essential oils can therefore be considered as potential natural pharmaceutical resources for cancer management.

Chemical Composition and Biological Activities of Essential Oils from Peels of Three Citrus Species

BACKGROUND

Fruit peels are generally underutilized byproducts of the food industry, although they are valuable sources of bioactive compounds. The aim of this study is to evaluate a new application for three Citrus peel EOs as bio-herbicides.

METHODS

After a micro-morphological evaluation of Citrus peels by SEM analysis, the phytochemical composition of the EOs of Citrus × bergamia Risso & Poit., Citrus × myrtifolia Raf., and Citrus limon (L.) Osbeck was characterized by GC/FID and GC/MS analyses. The in vitro phytotoxicity against germination and initial radical elongation of several crop and weed species was evaluated. Furthermore, the eco-compatibility of these EOs has been assessed by the brine shrimp (Artemia salina) lethality assay.

RESULTS

SEM analysis highlighted the morphometric differences of the schizolysigenous pockets among the peels of the three Citrus species. Oxygenated monoterpenes are the main constituents in C. × bergamia (51.09%), whereas monoterpene hydrocarbons represent the most abundant compounds in C. × myrtifolia (82.15%) and C. limon (80.33%) EOs. They showed marked and selective phytotoxic activity in vitro, often at very low concentration (0.1 μg/mL) against all plant species investigated, without showing any toxicity on Artemia salina, opening the perspective of their use as safe bio-herbicides.

Chemical Composition and in Vitro Antimicrobial, Cytotoxic, and Central Nervous System Activities of the Essential Oils of Citrus medica L. cv. 'Liscia' and C. medica cv. 'Rugosa' Cultivated in Southern Italy

Citrus medica cv. ‘liscia’ and C. medica cv. ‘rugosa’ are two taxa of citron, belonging to the biodiversity of South Italy, in particular of Amalfi Coast, in the Campania region. The chemical composition of the essential oils (EOs) from fruit peels of both C. medica cultivars was studied by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses. In all, 100 compounds were identified, 82 for C. medica cv. ‘liscia’, accounting for 91.4% of the total oil, and 88 for C. medica cv. ‘rugosa’, accounting for 92.0% of the total oil. Monoterpene hydrocarbons are the main constituents in both oils of C. medica cv. ‘liscia’ (79.1%) and C. medica cv. ‘rugosa’ (80.2%). In both oils, limonene (67.2%–62.8%) and camphene (8.5%–10.9%) are the main constituents. The antimicrobial activity of the EOs was assayed against some bacterial strains: Bacillus cereus (DSM 4313), Bacillus cereus (DSM 4384), Staphylococcus aureus (DSM 25693), Pseudomonas aeruginosa (ATCC 50071), and Escherichia coli (DSM 8579). Low concentrations of C. medica cv. ‘rugosa’ EO showed an inhibitory effect on P. aeruginosa and higher concentrations inhibited more B. cereus (4384) and E. coli than S. aureus. The cytotoxicity of the EO was evaluated against SH-SY5Y cell line. The influence of the EO on the expression of adenylate cyclase 1 (ADCY1) was also studied. The antimicrobial activity registered confirm their traditional uses as food preserving agents and led us to hypothesize the possible use of these oils as antimicrobials. The alterations in ADCY1 expression suggested a role for limonene in effects on the central nervous system.

Phototoxicity of herbal plants and herbal products

Plants are used by humans in daily life in many different ways, including as food, herbal medicines, and cosmetics. Unfortunately, many natural plants and their chemical constituents are photocytotoxic and photogenotoxic, and these phototoxic phytochemicals are widely present in many different plant families. To date, information concerning the phototoxicity and photogenotoxicity of many plants and their chemical constituents is limited. In this review, we discuss phototoxic plants and their major phototoxic constituents; routes of human exposure; phototoxicity of these plants and their constituents; general mechanisms of phototoxicity of plants and phototoxic components; and several representative phototoxic plants and their photoactive chemical constituents.

Comparative study on the antioxidant capacity and cholinesterase inhibitory activity of Citrus aurantifolia Swingle, C. aurantium L., and C. bergamia Risso and Poit. peel essential oils

The interest in medicinal plant research and in the aroma-therapeutic effects of essential oils in humans has increased in recent years, especially for the treatment of pathologies of relevant social impact such as Alzheimer's disease. The present study was taken up to evaluate the antioxidant capacity and the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity of the peel essential oils from three Citrus species, C. aurantifolia Swingle, C. aurantium L., and C. bergamia Risso & Poit. Essential oils were analyzed by GC and GC-MS and they contain mainly limonene, α-pinene, β-pinene, γ-terpinene, and linalyl acetate. C. aurantifolia oil showed the highest radical scavenging activity on ABTS assay (IC₅₀ value of 19.6 μg/mL), while C. bergamia exhibited a good antioxidant activity evaluated by the β-carotene bleaching test (IC₅₀ = 42.6 μg/mL after 60 min of incubation). C. aurantifolia inhibited more selectively AChE. Obtained data suggest a potential use of Citrus oils as a valuable new flavor with functional properties for food or nutraceutical products with particular relevance to supplements for the elderly.

PRACTICAL APPLICATION

The demonstrated antioxidant activity and procholinesterase properties of Citrus essential oils suggested their use as a new potential source of natural antioxidant to added as extra-nutrient for using in food industries as a valuable new flavor with functional properties for food or nutraceutical products with particular relevance to supplements for the elderly.