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Plant Profiler

Avocado (Persea americana)


Persea americana
Synonyms / Common Names / Related Terms
Abokado, aguacate, ahuacate, ahuacatl, alligator pear, avocado pear, Avocato, Persea americana, Persea americana var. drymifolia Blake, Persea gratissima, Persea leiogyna, Persea nubigena var. guatamalensis L., Persea persea, Laurus persea.






Mechanism of Action

Pharmacology:

  • Constituents: The applicable parts of avocado are the fruit, leaves, and seed. Avocado contains protein, fiber, manganese, phosphorous, iron, potassium, vitamin E, vitamin C, beta-carotene, thiamin, riboflavin, nicotinic acid, and folate.
  • Anti-carcinogenic effects: Persenone A, an avocado component was applied twice to mouse skin 30 minutes prior to application of each treatment of tumor-inducer 12-O-tetradecanoylphorbol-13-acetate (TPA). It reduced the formation of hydrogen peroxide (H2O2) by 50% (p < 0.01) in an animal in vivo experiment. The projected mechanism of action for this effect is inhibition of superoxide generation from leukocytes. The antioxidant activity on mouse skin may also be due to inhibition of cyclooxygenase-2 (COX-2) by persenone A. A COX-2 inhibitor reduced H2O2 formation induced by double treatment of TPA. Persenone A inhibited nitric oxide synthase (iNOS) and COX-2 protein expression in mouse macrophage cell line RAW 264.7 and nitric oxide (NO). COX-2, iNOS, and NO are involved in biochemical processes responsible for inflammatory diseases, including cancer. Suppression of overproduction of NO in inflammatory cells and enzyme suppression (COX-2 and iNOS) may play a role in carcinogenesis prevention.1
  • Avocado, at a concentration of 200mcg/mL, inhibited inducible nitric oxide synthase (iNOS) at a rate equal to 89.7% +/-1.2% in RAW 264.7 cells in vitro. Cell viability at this concentration was 100%.13
  • The tumor-protective effect of avocado in chemically induced mammary cancer in rats was speculated to be due to high amounts of polyunsaturated acids (linolenic and alpha-linolenic acid). The anti-carcinogenic effect exhibited by olive oil is thought to be due to monounsaturated fatty acids present, including oleic acid, palmitic acid, and stearic acid. Avocado oil and olive oil were found to have similar amounts of free fatty acids, but it is hypothesized that differences in their effects on cancer development is related to the interaction of these acids with factors that promote tumor development. Avocado contains a higher percentage of monounsaturated fatty acids than polyunsaturated and saturated fatty acids.14
  • Anti-inflammatory effects: Avocado/soybean unsaponifiables (ASU) have been shown to reduce cytokines, prostaglandin E2 and metalloproteinase production by human chondrocytes. This finding suggests a potential role for ASU in reducing the harmful effects of IL-1beta in cartilage.11,12 There is also evidence that ASU can increase aggrecan synthesis and reduce catabolic and proinflammatory mediator production by chondrocytes. These results suggest that ASU could have structure modifying effects in osteoarthritis by inhibiting cartilage degradation and promoting cartilage repair.10 ASU has also been shown to reverse the effect of IL-1beta on gingival fibroblasts for metalloproteinases. This suggests a potential role for ASU in preventing the harmful effects of IL-1beta during periodontal disease.15
  • Preliminary results suggest that ASU may be beneficial in the treatment of periodontitis or gingival inflammation. Gingival tissue from two healthy adults was incubated with ASU for 15 minutes, incubated with human leukocyte elastase (HLE) for 2 hours, and evaluated. ASU significantly protected gingival elastic fibers from proteolytic degradation of gingival matrix macromolecules by HLE in vivo. Proteolytic degradation and alteration of gingival matrix macromolecules by HLE resulted in an inflammatory process.2
  • Anti-oxidative and chemo preventative effects: Persenone A and B can be extracted from avocado; they function as antioxidants, and may be effective chemo preventive agents in inflammation-associated carcinogens.1
  • Chondroprotective effects: An experimental in vivo model for studying cartilage destruction was used to study the possible chondroprotective effect of the unsaponifiable constituents of avocado, soya and their combination at a ratio of 1:2. ASU and avocado alone caused significant chondroprotective effects compared to controls in an in vivo model of cartilage destruction. Possible mechanisms of action for this effect include the presence of free radical scavengers, tocopherol and beta-sitosterol, in ASU. Free radical damage is likely involved in cartilage degradation. ASU may also inhibit interleukin-1 (IL-1), which causes cartilage breakdown. IL-1 is released from mononuclear cells, and avocado and ASU have both caused inhibition of mononuclear influx into the granulomatous tissue around cartilage.16
  • Cultured bovine articular chondrocytes were treated with various concentrations of ASU, in order to establish the mechanism of action of ASU on articular chondrocytes that may account for the beneficial effects on cartilage metabolism. ASU stimulated the production of transforming growth factors beta-1 (TGF beta-1), TGF beta-2, and plasminogen activator inhibitor 1 (PAI-1). These elements may be involved in the prevention of cartilage degradation and promotion of matrix synthesis required in the repair of articular cartilage. The increased production of matrix metalloproteases, including collagenase and stromelysin by chondrocytes stimulated by interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha), are thought to be responsible for the erosion of cartilage that occurs in osteoarthritis.17
  • Hemolytic effects: Extracts from avocado seeds can cause hemolysis of fresh washed erythrocytes.18
  • Lysyl oxidase inhibitory effects: Compound C, isolated from avocado seed oil, inhibited lysyl oxidase activity in vivo and in vitro. Its activity is increased in the presence of tissue remodeling, as in burn scars, wound healing, hepatic fibrosis, granuloma, and lung fibrosis. The lysyl oxidase inhibitory activity of avocado seed oil may explain its use in the treatment of connective tissue disorders.9
  • The active constituent in avocado oil is believed, through its ability to inhibit lysyl oxidase activity, to decrease collagen cross-linking, resulting in an increased rate of collagen degradation in vivo. The active constituent responsible for this activity is found in the lipid fraction in the seed oil and unsaponifiable fractions of avocado oil. Theoretically, this effect may play a role in the treatment of certain connective tissue disorders where collagen accumulation is present.19
  • Plasma lipid lowering effects: Several clinical trials have demonstrated that diets rich in avocado can lower plasma lipids.7,3,4,5,8 The cholesterol lowering and skin soothing/healing effects may be due to the high content of unsaturated fatty acids and other compounds including tocopherols, oleic acid, vitamin E, sterols and volatile oils.

Pharmacodynamics/Kinetics:

  • Initial response of ASU became statistically superior to placebo treatment after two months of treatment. The effect continued to increase up to six months and lasted for at least two months after treatment was discontinued.6

References
  1. Kim, O. K., Murakami, A., Nakamura, Y., Takeda, N., Yoshizumi, H., and Ohigashi, H. Novel nitric oxide and superoxide generation inhibitors, persenone A and B, from avocado fruit. J Agric Food Chem  2000;48(5):1557-1563. 10820058
  2. Kut, C., Assoumou, A., Dridi, M., Bonnefoix, M., Gogly, B., Pellat, B., Guillou, G. B., and Godeau, G. Morphometric analysis of human gingival elastic fibres degradation by human leukocyte elastase protective effect of avocado and soybean unsaponifiables (ASU). Pathol Biol (Paris) 1998;46(7):571-576. 9842576
  3. Carranza, J., Alvizouri, M., Alvarado, M. R., Chavez, F., Gomez, M., and Herrera, J. E. [Effects of avocado on the level of blood lipids in patients with phenotype II and IV dyslipidemias]. Arch Inst Cardiol Mex  1995;65(4):342-348. 8561655
  4. Lerman-Garber, I., Ichazo-Cerro, S., Zamora-Gonzalez, J., Cardoso-Saldana, G., and Posadas-Romero, C. Effect of a high-monounsaturated fat diet enriched with avocado in NIDDM patients. Diabetes Care 1994;17(4):311-315. 8026287
  5. Colquhoun, D. M., Moores, D., Somerset, S. M., and Humphries, J. A. Comparison of the effects on lipoproteins and apolipoproteins of a diet high in monounsaturated fatty acids, enriched with avocado, and a high-carbohydrate diet. Am J Clin Nutr  1992;56(4):671-677. 1414966
  6. Maheu, E., Mazieres, B., Valat, J. P., Loyau, G., Le, Loet, X, Bourgeois, P., Grouin, J. M., and Rozenberg, S. Symptomatic efficacy of avocado/soybean unsaponifiables in the treatment of osteoarthritis of the knee and hip: a prospective, randomized, double-blind, placebo-controlled, multicenter clinical trial with a six-month treatment period and a two-month followup demonstrating a persistent effect. Arthritis Rheum  1998;41(1):81-91. 9433873
  7. Lopez Ledesma R., Frati Munari, A. C., Hernandez Dominguez, B. C., Cervantes, Montalvo S., Hernandez Luna, M. H., Juarez, C., and Moran, Lira S. Monounsaturated fatty acid (avocado) rich diet for mild hypercholesterolemia. Arch Med Res  1996;27(4):519-523. 8987188
  8. Alvizouri-Munoz, M., Carranza-Madrigal, J., Herrera-Abarca, J. E., Chavez-Carbajal, F., and Amezcua-Gastelum, J. L. Effects of avocado as a source of monounsaturated fatty acids on plasma lipid levels. Arch Med Res  1992;23(4):163-167. 1308699
  9. Werman, M. J., Mokady, S., Neeman, I., Auslaender, L., and Zeidler, A. The effect of avocado oils on some liver characteristics in growing rats. Food Chem Toxicol  1989;27(5):279-282. 2744658
  10. Henrotin, Y. E., Sanchez, C., Deberg, M. A., Piccardi, N., Guillou, G. B., Msika, P., and Reginster, J. Y. Avocado/soybean unsaponifiables increase aggrecan synthesis and reduce catabolic and proinflammatory mediator production by human osteoarthritic chondrocytes. J Rheumatol  2003;30(8):1825-1834. 12913942
  11. Henrotin, Y. E., Labasse, A. H., Jaspar, J. M., De Groote, D. D., Zheng, S. X., Guillou, G. B., and Reginster, J. Y. Effects of three avocado/soybean unsaponifiable mixtures on metalloproteinases, cytokines and prostaglandin E2 production by human articular chondrocytes. Clin Rheumatol  1998;17(1):31-39. 9586676
  12. Mauviel, A., Loyau, G., and Pujol, J. P. [Effect of unsaponifiable extracts of avocado and soybean (Piascledine) on the collagenolytic action of cultures of human rheumatoid synoviocytes and rabbit articular chondrocytes treated with interleukin-1]. Rev Rhum Mal Osteoartic  1991;58(4):241-245. 1647544
  13. Kim, O. K., Murakami, A., Nakamura, Y., and Ohigashi, H. Screening of edible Japanese plants for nitric oxide generation inhibitory activities in RAW 264.7 cells. Cancer Lett  3-13-1998;125(1-2):199-207. 9566716
  14. Zusman, I., Gurevich, P., Madar, Z., Nyska, A., Korol, D., Timar, B., and Zuckerman, A. Tumor-promoting and tumor-protective effects of high-fat diets on chemically induced mammary cancer in rats. Anticancer Res  1997;17(1A):349-356. 9066676
  15. Kut-Lasserre, C., Miller, C. C., Ejeil, A. L., Gogly, B., Dridi, M., Piccardi, N., Guillou, B., Pellat, B., and Godeau, G. Effect of avocado and soybean unsaponifiables on gelatinase A (MMP-2), stromelysin 1 (MMP-3), and tissue inhibitors of matrix metalloproteinase. J Periodontol  2001;72(12):1685-1694. 11811504
  16. Khayyal, M. T. and el Ghazaly, M. A. The possible "chondroprotective" effect of the unsaponifiable constituents of avocado and soya in vivo. Drugs Exp Clin.Res  1998;24(1):41-50. 9604147
  17. Boumediene, K., Felisaz, N., Bogdanowicz, P., Galera, P., Guillou, G. B., and Pujol, J. P. Avocado/soya unsaponifiables enhance the expression of transforming growth factor beta1 and beta2 in cultured articular chondrocytes. Arthritis Rheum  1999;42(1):148-156. 9920025
  18. Yaakobovich, Y. and Neeman, I. Partial isolation and characterisation of a hemagglutinating factor from avocado seed. Arch Toxicol Suppl 1983;6:52-57. 6578749
  19. Werman, M. J., Mokady, S., Nimni, M. E., and Neeman, I. The effect of various avocado oils on skin collagen metabolism. Connect Tissue Res  1991;26(1-2):1-10. 1676360




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