In Vitro Antioxidant and Cancer Inhibitory Activity of a Colored Avocado Seed Extract.

Avocado (Persea americana) seeds have been used traditionally for a number of health-related indications. Because of its high polyphenol content, we investigated the potential antioxidant and anticancer effects of a colored avocado seed extract (CASE). CASE exhibited an oxygen radical acceptance capacity value of 2012 ± 300 trolox equivalents/mg. CASE reduced lipid hydroperoxide formation in an oil-in-water emulsion (33% reduction at 500 µg/mL). CASE dose-dependently reduced the viability of human breast (MCF7), lung (H1299), colon (HT29), and prostate (LNCaP) cancer cells in vitro. The half maximal inhibitory concentrations ranged from 19 to 132 µg/mL after treatment for 48 h. CASE treatment downregulated the expression of cyclin D1 and E2 in LNCaP cells. This was associated with cell G0/G1 phase cycle arrest. CASE also dose-dependently induced apoptosis in LNCaP cells. CASE reduced nuclear translocation of nuclear factor κB, a prosurvival signal. Further studies are needed to examine these effects in in vivo models.

Avocado (Persea americana) seed as a source of bioactive phytochemicals.

The pulp of avocado (Persea americana, Lauraceae) has been reported to have beneficial cardiovascular health effects. Avocado oil is used for dermatological applications and its unsaponifiable portion is reported to have beneficial effects against osteoarthritis. Although the seed represents a considerable percentage of the total fruit, scientific research on the phytochemistry and biological effects of avocado seeds is in the nascent stages,. Currently, the seed represents an under-utilized resource and a waste issue for avocado processors. There is ethno-pharmacological information on the use of seeds for the treatment of health-related conditions, especially in South American countries where avocados are endemic and currently grown on a large scale. Current research has shown that avocado seeds may improve hypercholesterolemia, and be useful in the treatment of hypertension, inflammatory conditions and diabetes. Seeds have also been found to possess insecticidal, fungicidal, and anti-microbial activities. The avocado seeds and rich in phenolic compounds, and these may play a role in the putative health effects. Historically, extracts of avocado seeds were also used as ink for writing and research in our laboratory has explored the potential colorant properties of a polyphenol oxidase-produced colored avocado seed extract. Here, we review the currently-available data on the bioactivity and other functional properties of avocado seeds. We discuss the strength of the available data, the putative active compounds, and potential directions for future studies.

Evaluation of the effect of concentration and duration of application of sodium ascorbate hydrogel on the bond strength of composite resin to bleached enamel.

AIM: The effect of different concentrations of hydrogel of sodium ascorbate on bond strength of bleached enamel for varying periods of time and the mode of failure was evaluated. MATERIALS AND METHODS: Seventy enamel surfaces were obtained from 35 human extracted premolars. Specimens were divided into four groups: no bleaching (control), bleaching with carbamide peroxide gel, bleaching and application of 10% / 20% sodium ascorbate hydrogel for 30, 60, 120 min. Surfaces were bonded with a total etch bonding system and composite resin. Specimens were tested for shear bond strength. Mode of failure was determined by stereomicroscope. Data were analyzed using a two-way analysis of variance, and Scheffe's post hoc test. RESULTS: Sodium ascorbate hydrogel application following bleaching increased the resin-enamel bond strength and was directly proportional to its duration of application. However, there was no difference in bond strength with an increase in the concentration of sodium ascorbate hydrogel. CONCLUSION: Immediate bonding of composite resin to bleached enamel is possible after treatment with antioxidant sodium ascorbate hydrogel.

A colored avocado seed extract as a potential natural colorant.

UNLABELLED: There is an increasing consumer demand for and scientific interest in new natural colorants. Avocado (Persea americana) seed when crushed with water develops an orange color (= 480 nm) in a time-dependent manner. Heat treatment of the seed prevented color development, whereas the addition of exogenous polyphenol oxidase (PPO), but not peroxidase restored color development. Color development was also inhibited by the addition of tropolone, an inhibitor of PPO. Color formation resulted in a decrease in the concentration of polyphenols indicating utilization for color formation. The orange color intensified as the pH was adjusted from 2.0 to 11.0, and these changes were only partially reversible when pH was adjusted from 7.5 to 11.0 in the presence of oxygen, but completely reversible when the pH was changed in the absence of oxygen. The color was found to be stable in solution at -18 °C for 2 mo. These results suggest that the avocado seed may be a potential source of natural colorant, and that color development is PPO-dependent. PRACTICAL APPLICATION: There is growing public and scientific interest in the development of natural alternatives to synthetic colorants in foods. Extracts of turmeric, paprika, and beets are examples of food-derived natural colorants. Avocado seeds, which represent an under-utilized waste stream, form a stable orange color when crushed in the presence of air. Our data indicate that avocado seed represents a potential source of new natural colorants for use in foods.