Antimicrobial activity and inhibition of aflatoxin B₁ formation by olive plant tissue constituents

Abstract

Ethanolic extracts of olive callus tissues, added at 0.5 or 1.0% to media on which Aspergillus flavus was grown, inhibited aflatoxin production by 90% without inhibiting the fungal growth. The extract was found to contain mainly caffeic acid and, to a lesser extent, catechin and coumarins. The fungicidal and bactericidal activity of caffeic acid, catechin, coumarin and p-, o- or m-coumaric acid were tested and only caffeic acid and o-coumaric acid inhibited aflatoxin production. The inhibitory effect had no correlation with the growth of the fungus. Only coumarin at 10 mmol/1 totally inhibited fungal growth. Of the phenolic constituents of callus tissues tested, catechin and caffeic acid (10 mmol/l) showed bactericidal activity towards Pseudomonas aeruginosa and Staphylococcus aureus.

Natural antimicrobials from plants

“…Sakanaka et al (1989Sakanaka et al ( , 1990 reported the antibacterial effect of extracts of Japanese Rodriguez et al (1988); Sakanaka et al (1989Sakanaka et al ( , 1990, Diker et al (1991), Toda et al (1989Toda et al ( , 1991, Torres, et al (1987). Ayaz et al (1980);Tassou (1993);Garrido-Femandex and Vaughn (1978);Fleming et al (1973); Thompson (1991); Robach and Pierson (1979); Robach et al (1977); Payne et al (1989); Davidson (1983); Sakanaka et al (1989Sakanaka et al ( , 1990; Ruiz- Barba et al (1990, 1993) Rico-Munoz et al (1987Paster et al (1988); Davidson and Branen (1980);Person et al (1980); Ruiz- Barba and Diez (1989);Stem et al (1979).…”

Effects of Cymbopogon citratus L. essential oil on the growth, morphogenesis and aflatoxin production of Aspergillus flavus ML2‐strain

“…This result was confirmed by using bioassays involving Bacillus megaterium and Artemia salina. Ethanolic extracts of olive callus tissues added at 0.5 -1.0% to media of A. flavus inhibited aflatoxin B 1 production by 90% without inhibiting fungal growth (Paster et al 1988). 500 ppm Allium cepa oil inhibited aflatoxin production by 95% and 76% from A. flavus and A. parasiticus, respectively.…”

Use of Solid Residue from the Olive Industry

“…Of special interest is the extract's antimicrobial activity, in the possibility of utilizing them as alternative food additives (Markin et al, 2003;Tassou and Nychas, 1994). Similarly, various authors have reported on the antibacterial activity of the phenolic compounds of the olive tree (Tassou and Nychas, 1995;Tranter, 1993;Rodríguez et al, 1988;Paster et al, 1988;Nychas et al, 1990). Other studies include one conducted on the effect of an aqueous extract of olive leaf on the thyroid gland in laboratory animals (Al-Qarawi et al, 2002), and another on the antioxidant activity of an olive leaf extract against sunflower oil oxidation (Farag et al, 2002).…”