Biological effects of essential oils - A review

An investigation of factors controlling healing and long term stability of intra-osseous titanium implants to restore masticatory function in dogs revealed that an integrity of the good anchorage of the implant requires: (1) Non-traumatic surgical preparation of soft and hard tissues and a mechanically and chemically clean implant. (2) Primary closure of the mucoperiosteal flap, to isolate the implant site from the oral cavity until a biological barrier has been reestablished. (3) Oral hygiene to prevent gingival inflammation. Provided these precautions are taken, it is possible to subject dental prostheses, connected to the implants, to unlimited masticatory load. With these precautions such implants were found to tolerate ordinary use in dogs for periods of more than 5 years without signs of tissue injury or other indications of rejection phenomena.Macroscopic clinical investigation, stereomicroscopy, roentgenography and light microscopy of the implant site in situ and after removal from the body showed...

Intra-osseous anchorage of dental prostheses. I. Experimental studies.

A wide array of phenolic substances, particularly those present in edible and medicinal plants, have been reported to possess substantial anticarcinogenic and antimutagenic activities. The majority of naturally occurring phenolics retain antioxidative and anti-inflammatory properties which appear to contribute to their chemopreventive or chemoprotective activity. Cyclooxygenase-2 (COX-2) inducible and nitric oxide synthase (iNOS) are important enzymes that mediate inflammatory processes. Improper up-regulation of COX-2 and/or iNOS has been associated with pathophysiology of certain types of human cancers as well as inflammatory disorders. Since inflammation is closely linked to tumor promotion, substances with potent anti-inflammatory activities are anticipated to exert chemopreventive effects on carcinogenesis, particularly in the promotion stage. Examples are curcumin, a yellow pigment of turmeric (Curcuma longa L., Zingiberaceae), the green tea polyphenol epigallocatechin gallate (EGCG), and resveratrol from grapes (Vitis vinifera, Vitaceae) that strongly suppress tumor promotion. Recent studies have demonstrated that eukaryotic transcription factor nuclear factor-kappa B (NF-kappa B) is involved in regulation of COX-2 and iNOS expression. Several chemopreventive phytochemicals have been shown to inhibit COX-2 and iNOS expression by blocking improper NF-kappa B activation. Multiple lines of compelling evidence indicate that extracellular-regulated protein kinase and p38 mitogen-activated protein kinase are key elements of the intracellular signaling cascades responsible for NF-kappa B activation in response to a wide array of external stimuli. Curcumin, EGCG and resveratrol have been shown to suppress activation of NF-kappa B. One of the plausible mechanisms underlying inhibition of NF-kappa B activation by aforementioned phytochemicals involves repression of degradation of the inhibitory unit I kappa B alpha, which hampers subsequent nuclear translocation of the functionally active subunit of NF-kappa B.

Molecular mechanisms underlying chemopreventive activities of anti-inflammatory phytochemicals: down-regulation of COX-2 and iNOS through suppression of NF-kappa B activation.

Background Patients with head-and-neck cancers who are free of disease after local therapy remain at high risk for both recurrent and second primary tumors Retinoids have proved efficacious in the treatment of premalignant oral lesions and are promising agents for the prevention of epithelial carcinogenesis Methods We prospectively studied 103 patients who were disease-free after primary treatment for squamous-cell cancers of the larynx, pharynx, or oral cavity After completion of surgery or radiotherapy (or both), these patients were randomly assigned to receive either isotretinoin (13-cis-retinoic acid) (50 to 100 mg per square meter of body-surface area per day) or placebo, to be taken daily for 12 months Results There were no significant differences between the two groups in the number of local, regional, or distant recurrences of the primary cancers However, the isotretinoin group had significantly fewer second primary tumors After a median follow-up of 32 months, only 2 patients (4

https://www.nejm.org/doi/pdf/10.1056/NEJM199009203231205

Prevention of second primary tumors with isotretinoin in squamous-cell carcinoma of the head and neck.

https://faculty.missouri.edu/~glaserr/3700s14/Antioxidant_Carotenoids_2005.pdf

Carotenoid actions and their relation to health and disease.

An animal model for mucositis induced by cancer chemotherapy.

beta-Carotene was found to significantly inhibit the formation of 7,12-dimethylbenz[a]anthracene (DMBA)-induced squamous cell carcinoma of hamster buccal pouch when applied topically on days alternate to the application of 0.25% DMBA in heavy mineral oil thrice weekly for 22 weeks. An initial experiment utilized 40 male young adult Syrian hamsters divided into four equal groups. Group 1 had DMBA applied to left buccal pouches thrice weekly. Group 2 had DMBA applied as in group 1 but also beta-carotene thrice weekly on days alternate to the DMBA application. Group 3 animals were painted with only beta-carotene and group 4 animals were untreated controls. In a second experiment with 80 animals, beta-carotene was found to inhibit oral carcinogenesis in an initiation--promotion hamster buccal pouch system using 0.1% DMBA as initiator and 40% benzoyl peroxide as promoter. beta-Carotene inhibited both initiation and promotion.

Inhibition of experimental oral carcinogenesis by topical beta carotene

Eighty young adult male and female Syrian golden hamsters (Mesocricetus auratus) were divided into 4 equal experimental groups. In group I animals the left buccal pouch was painted three times weekly with a 0.5% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in heavy mineral oil. In group 2 animals the left buccal pouch was similarly painted with DMBA, but the animals also received orally 10 mg vitamin E (dl-alpha-tocopherol) in peanut oil twice weekly on alternate days with DMBA painting. Group 1 animals received a similar amount of peanut oil vehicle, group 3 animals received only vitamin E (vitamin E controls) in peanut oil, and group 4 animals served as untreated controls receiving only peanut oil. Four animals in each group (2 males and 2 females) were killed at 8, 10, 12, 14, and 16 weeks. Buccal pouches were photographed and excised, and tumors were noted and measured in the left buccal pouches. In group 2 animals receiving vitamin E, tumor formation was significantly delayed, so that by 14-16 weeks there were fewer tumors and their average size was smaller than that of tumors in group 1 animals that were painted with DMBA but received no vitamin E supplement. In group 2 there was also less invasion of underlying tissues and less surface necrosis.

Oral Mucosal Carcinogenesis in Hamsters: Inhibition by Vitamin E

An extract of Spirulina-Dunaliella algae was shown to prevent tumor development in hamster buccal pouch when a 0.1% solution of 7,12-dimethylbenz[a]anthracene (DMBA) in mineral oil was applied topically three times weekly for 28 weeks. The algae extract was delivered by mouth in continued dosages of 140 micrograms in 0.4 ml mineral oil three times per week. After 28 weeks, the animals given vehicle and untreated controls all presented gross tumors of the right buccal pouch. Animals fed canthaxanthin presented a notably and statistically significant reduction in tumor number and size compared with controls. Animals fed beta-carotene demonstrated a smaller but statistically significant reduction in tumor number and size. The algae animals presented a complete absence of gross tumors. However, microscopic sections of the buccal pouch in the algae group showed localized areas of dysplasia and early carcinoma-in-situ undergoing destruction.

Gerald Shklar

Papers

An animal model for mucositis induced by cancer chemotherapy.

Inhibition of experimental oral carcinogenesis by topical beta carotene

Oral Mucosal Carcinogenesis in Hamsters: Inhibition by Vitamin E

Prevention of experimental oral cancer by extracts of Spirulina‐Dunaliella algae

Lichen planus as an oral ulcerative disease