Dissertation

Pharmaceutical Applications and Toxicity of Extracted Alkenones from Marine Isochrysis Algae

McIntosh, Kyle

2019

Overview

Isochrysis is a commercially available marine algae used for animal feed, human nutrient supplements, and biodiesel. The Isochrysis galbana species is one of four genera of haptophytes that produces unique, long-chain lipids known as alkenones. However, there is a lack of physical characteristics and toxicity data for alkenones in animals, thus, limiting their use in humans. In the first aim of this study, alkenones derived from Isochrysis sp. were evaluated for their chemical structure characteristics as an alternative for waxes used in personal care products. The melting point of the alkenone was determined (71.1–77.4°C), and their thickening capability in five emollients was evaluated and compared to microcrystalline wax and ozokerite. Alkenones showed compatibility with three emollients, isopropyl isostearate, C12-C15 alkyl benzoate, and ethylhexyl methyxycinnamate, and they thickened the emollients similar to the other tested waxes. Lipsticks and lip balms were formulated with and without alkenones. All products remained stable at room temperature for 10 weeks. Lipstick formulated with alkenones was the most resistant to high temperature. Finally, alkenones were compared to three cosmetic thickening waxes in creams. Viscosity, rheology and stability of the creams were evaluated. All creams had a gel-like behavior. Overall, the alkenones in these formulas were comparable to the other three waxes. Thus, alkenones can offer a potential green choice as a new personal care structuring compound.For the second aim of this study, we performed acute oral, acute dermal and repeated 28-day dermal toxicity studies using female SAS (an acronym for the company SASCO where the colony was bred) Sprague Dawley rats. Our behavioral studies (level of grooming, eye opening, walking, exploring, body posture, breathing, scratching, and nose flattening) indicated that the specific alkenones had no visible behavioral effects at oral doses up to 4000 mg/kg. In addition, there were no significant changes in food consumption or body weight, and there was no significant histopathological changes in the liver, kidneys, spleen, heart or skin compared to animals treated with vehicle. In the acute and chronic dermal toxicity studies, the alkenones produced less irritation and did not significantly damage the skin based on the Draize skin reaction scale and transepidermal water loss readings compared to the positive control, 1% sodium lauryl sulfate. Overall, our results indicated that alkenones are safe in female Sprague Dawley rats, suggesting that they could be used for both oral and dermal formulations, although additional studies would be required before these alkenones could be applied to human personal care products.

• Publisher: ProQuest Dissertations & Theses
• Subject: Health sciences / Pharmaceutical sciences / Pharmacology / Physiology / Toxicology
• ISBN: 9781687971951, 1687971951