Activity of preparations from Spilanthes oleracea, propolis, Nigella sativa, and black garlic on different microorganisms involved in oral diseases and on total human salivary bacteria: A pilot study

Propolis Use in Dentistry: A Narrative Review of Its Preventive and Therapeutic Applications

Propolis is a resinous substance produced naturally by bees, and it consists of the exudates of plants mixed with enzymes, wax, and pollen. Propolis continues to gain considerable scientific interest due to its potential health benefits. The modern-day use of propolis in pharmaceutical preparations, such as toothpastes, mouthwashes, chewable tablets, mucoadhesive gels, and sprays, is increasing. However, the effectiveness of using propolis-containing pharmaceuticals in dentistry is not clear. The present paper aims to review the literature on the dental applications of propolis in preventive dentistry, periodontics, oral medicine, and restorative dentistry and discuss its clinical effectiveness. A literature search was conducted using Scopus, PubMed, and Web of Science databases. In total, 104 studies were included, of which 46 were laboratory studies, 5 animal studies, and 53 human clinical studies. Overall, the laboratory studies revealed a range of antimicrobial effects of propolis on oral pathogens. Clinical investigations of propolis in biofilm and dental caries control as well as adjuvant periodontal therapies reported positive outcomes in terms of plaque control, pathogenic microbial count reduction, and periodontal tissue inflammation control. Additional investigations included the use of propolis for the management of recurrent aphthous stomatitis, oral mucositis, and cavity disinfection after caries removal as well as the development of a range of restorative dental materials. Based on the reported outcomes of the studies, the clinical usage of propolis has potential. However, the majority of the evidence is derived from studies with flaws in their methodological design, making their results and conclusions questionable. As a consequence, properly designed and well-reported clinical studies are required to affirm the effectiveness of propolis for dental applications. Additionally, the safety of propolis and the optimal concentrations and extraction methods for its clinical use warrant further investigation. Utilisation of standardised propolis extracts will help in quality control of propolis-based products and lead to the achievement of reproducible outcomes in research studies.

Biological Potentials and Phytochemical Constituents of Raw and Roasted Nigella arvensis and Nigella sativa

Nigella species are widely used to cure various ailments. Their health benefits, particularly from the seed oils, could be attributed to the presence of a variety of bioactive components. Roasting is a critical process that has historically been used to facilitate oil extraction and enhance flavor; it may also alter the chemical composition and biological properties of the Nigella seed. The aim of this study was to investigate the effect of the roasting process on the composition of the bioactive components and the biological activities of Nigella arvensis and Nigella sativa seed extracts. Our preliminary study showed that seeds roasted at 50 °C exhibited potent antimicrobial activities; therefore, this temperature was selected for roasting Nigella seeds. For extraction, raw and roasted seed samples were macerated in methanol. The antimicrobial activities against Streptococcus agalactiae, Streptococcus epidermidis, Streptococcus pyogenes, Candida albicans, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Klebsiella oxytoca were determined by measuring the diameter of the zone of inhibition. The cell viability of extracts was tested in a colon carcinoma cell line, HCT-116, by using a microculture tetrazolium technique (MTT) assay. Amino acids were extracted and quantified using an automatic amino acid analyzer. Then, gas chromatography–mass spectrometry (GC–MS) analysis was performed to identify the chemical constituents and fatty acids. As a result, the extracts of raw and roasted seeds in both Nigella species showed strong inhibition against Klebsiella oxytoca, and the raw seed extract of N.arvensis demonstrated moderate inhibition against S. pyogenes. The findings of the MTT assay indicated that all the extracts significantly decreased cancer cell viability. Moreover, N. sativa species possessed higher contents of the measured amino acids, except tyrosine, cystine, and methionine. The GC–MS analysis of extracts showed the presence of 22 and 13 compounds in raw and roasted N. arvensis, respectively, and 9 and 11 compounds in raw and roasted N. sativa, respectively. However, heat treatment decreased the detectable components to 13 compounds in roasted N. arvensis and increased them in roasted N. sativa. These findings indicate that N. arvensis and N. sativa could be potential sources of anticancer and antimicrobials, where the bioactive compounds play a pivotal role as functional components.

Garlic (Allium sativum L.) Bioactives and Its Role in Alleviating Oral Pathologies

Garlic (Allium sativa L.) is a bulbous flowering plant belongs to the family of Amaryllidaceae and is a predominant horticultural crop originating from central Asia. Garlic and its products are chiefly used for culinary and therapeutic purposes in many countries. Bulbs of raw garlic have been investigated for their role in oral health, which are ascribed to a myriad of biologically active compounds such as alliin, allicin, methiin, S-allylcysteine (SAC), diallyl sulfide (DAS), S-ally-mercapto cysteine (SAMC), diallyl disulphide (DADS), diallyl trisulfide (DATS) and methyl allyl disulphide. A systematic review was conducted following the PRISMA statement. Scopus, PubMed, Clinicaltrials.gov, and Science direct databases were searched between 12 April 2021 to 4 September 2021. A total of 148 studies were included and the qualitative synthesis phytochemical profile of GE, biological activities, therapeutic applications of garlic extract (GE) in oral health care system, and its mechanism of action in curing various oral pathologies have been discussed. Furthermore, the safety of incorporation of GE as food supplements is also critically discussed. To conclude, GE could conceivably make a treatment recourse for patients suffering from diverse oral diseases.

Chemical Composition Related to Antimicrobial Activity of Moroccan Nigella sativa L. Extracts and Isolated Fractions

Background

Nigella sativa L. (NS) is an aromatic and medicinal plant commonly used in Mediterranean cuisine. Its grains contain a large amount of fixed oil and have many therapeutic virtues and medicinal properties (antioxidant, antidiabetic, antimicrobial, and anticancer).

Aim

The aim of this work is to study the antimicrobial activity of Nigella sativa L. extracts and separated fractions on various pathogenic strains and to correlate that with its chemical composition.

Methods

Extracts from Moroccan Nigella sativa seeds were extracted using successive organic solvents, and their hexane and acetone extracts were separated by column chromatography. The chemical composition of extracts, fractions, and essential oil was determined by GC-MS and HPLC-DAD. Extracts and fractions were evaluated for antimicrobial activity through disk diffusion against Gram-positive bacteria (Staphylococcus aureus, Bacillus cereus, and Listeria innocua), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and yeast (Candida pelliculosa) for 1 mg/mL concentration. Bacterial strains were followed to study their behaviors over time in different concentrations. The minimum inhibitory concentration of Nigella sativa essential oil was determined against Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Candida albicans. Results and Conclusion. Although hexane extract was active against both types of bacteria (Gram+ and Gram−), some of its fractions were specifically active against only one type. Fraction (SH4) had the highest activity (15 mm inhibitory diameter). Acetone extract was nonactive but surprisingly resulted in specific active fractions, and the most interesting one was (SA7) that had an inhibitory diameter of 13 mm. This antibacterial effect was related to fatty acids (linoleic and palmitic acids) in (SH4) and 17 pentatriacontene in (SA7). Moreover, the antifungal activity of hexane fractions (10–13 mm) was higher than hexane extract (8 mm), but for acetone, it was the opposite. Acetone extract had a higher activity (18 mm) than its fractions (8–12 mm), except for (SA7) (19 mm). Those inhibitions were attributed to gallic acid, cysteine, and apigenin in acetone extract and cysteine with ascorbic acid in fraction (SA7). Antifungal activity of the essential oil was more pronounced than the antibacterial one. Indeed, determined MICs in the first case were on the microgram scale (MIC = 8 μg/mL, Candida albicans), while in the second case, they were on the milligram scale (MIC = 0.96 mg/mL for Staphylococcus aureus, 0.5 mg/mL for Bacillus cereus, and 0.68 mg/mL for Escherichia coli). This antifungal activity was attributed to three major compounds beta-cymene, alpha-thujene, origanene, and thymoquinone. Results of strains behavior over time at different concentrations of the fractions showed all the curves went through a maximum around 20 hours and had a delay of expression of 5 hours at the start. Taking all results into count, Nigella sativa L. extracts and/or derived principles could form promising antimicrobial agents for therapeutical and industrial uses.

Antibacterial Properties of Organosulfur Compounds of Garlic (Allium sativum)

Garlic (Allium sativum), a popular food spice and flavoring agent, has also been used traditionally to treat various ailments especially bacterial infections for centuries in various cultures around the world. The principal phytochemicals that exhibit antibacterial activity are oil-soluble organosulfur compounds that include allicin, ajoenes, and allyl sulfides. The organosulfur compounds of garlic exhibit a range of antibacterial properties such as bactericidal, antibiofilm, antitoxin, and anti-quorum sensing activity against a wide range of bacteria including multi-drug resistant (MDR) strains. The reactive organosulfur compounds form disulfide bonds with free sulfhydryl groups of enzymes and compromise the integrity of the bacterial membrane. The World Health Organization (WHO) has recognized the development of antibiotic resistance as a global health concern and emphasizes antibiotic stewardship along with the urgent need to develop novel antibiotics. Multiple antibacterial effects of organosulfur compounds provide an excellent framework to develop them into novel antibiotics. The review provides a focused and comprehensive portrait of the status of garlic and its compounds as antibacterial agents. In addition, the emerging role of new technologies to harness the potential of garlic as a novel antibacterial agent is discussed.

Nigella sativa Oil Mouth Rinse Improves Chemotherapy-Induced Oral Mucositis in Patients with Acute Myeloid Leukemia

Objective

The present study aims at evaluating the beneficial effect of Nigella sativa (NS) oil mouth rinse in the management of chemotherapy- (CT-) induced oral mucositis (OM) in patients with acute myeloid leukemia (AML).

Methods

Fifty-four AML patients were participated in this study and randomly allocated to either the test group or a control group. The patients of the test group received NS oil mouth rinse during 28-day CT, while the participants of the control group received a "magic mouthwash" formula. The primary outcome of this study was the incidence and severity of CT-induced OM in terms of erythema and ulcer. The secondary outcomes were the pain severity score, swallowing function, and the salivary concentrations of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α).

Results

NS oil mouth rinse attenuated the progression of CT-induced OM compared with the control formula (AUC = 5.9 vs. 38.4, P < 0.05) and significantly decreased the erythema and ulceration scores (AUC of total OMAS = 11.4 vs. 85.9, P < 0.001) compared with the magic mouthwash formula. It also reduced the pain score and enabled all the participants of this group to consume normal food during treatment. It significantly decreased salivary IL-6 (AUC = 7376 vs. 16599, P < 0.001), while the changes of TNF-α levels were not significant (AUC = 676.9 vs. 885.2, P > 0.05).

Conclusions

NS oil mouth rinse is effective in attenuating the severity of CT-induced OM and improves the pain and swallowing function in AML patients.

Lactobacillus bulgaricus improves antioxidant capacity of black garlic in the prevention of gestational diabetes mellitus: a randomized control trial

Objectives:Lactobacillus bulgaricus may improve antioxidant capacity of black garlic in the prevention of gestational diabetes mellitus (GDM).

Methods: Black garlic was prepared with or without L. bulgaricus. Volatile and polysaccharides were analyzed by using LC-MS, Fourier Transform infrared (FTIR) and ¹³C nuclear magnetic resonance (NMR). The study design was parallel randomized controlled trial and 226 GDM patients were randomly assigned into BG (black garlic and L. bulgaricus) and CG (black garlic) groups, and allocation ratio was 1:1. The treatment duration was 40 weeks. Fasting blood glucose (FBG) and 1- and 2-h blood glucose (1hBG and 2hBG) after oral glucose tolerance test (OGTT) were detected. Antioxidant function of black garlic was determined by measuring plasma malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and total antioxidant capacity (T-AOC) in GDM patients. The comparison between two groups was made using two independent samples t test.

Results: The intake of nutrients was similar between two groups (P>0.05). L. bulgaricus promoted the transformation of the glucopyranoside to glucofuranoside. L. bulgaricus increased the abilities of black garlic for scavenging hydroxyl radicals, 2,2′-azino-bis (3-ethylbenzenthiazoline-6-sulfonic) acid (ABTS) and DPPH free radicals. L. bulgaricus reduced the levels of FBG, 1hBG and 2hBG, and incidence of perinatal complications (P<0.01). Plasma MDA level in the BG group was lower than in the CG group, whereas the levels of SOD, GSH-PX and T-AOC in the BG group were higher than in the CG group (P<0.01).

Conclusions:L. bulgaricus improves antioxidant capacity of black garlic in the prevention of GDM.