In this study, we investigated in vitro the potential of Trichoderma harzianum to produce bioactive secondary metabolites that can be used as alternatives to synthetic compounds. The study focused on analyzing two extracts of T. harzianum using ethyl acetate and n-butanol solvents with different polarities. The extracts were examined using phytochemical analysis to determine the content of polyphenols, flavonoids, tannins, and alkaloids. Thin-layer chromatography (TLC) and Gas chromatography-mass spectroscopy (GC-MS) analysis were used to profile volatile organic metabolites (VOCs) present in the extracts. Furthermore, the extracts were tested for their antifungal ability using the poison food technique. For measuring antioxidant activity, the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) test was used. Trichoderma harzianum was shown to have a significantly high content of tannins and alkaloids, with a noticeable difference between the two extracts. GC-MS analysis identified 33 potential compounds with numerous benefits that could be used in agriculture and the medicinal industry. Moreover, strong antifungal activity was identified against Sclerotinia sclerotiorum by 94.44%, Alternaria sp. by 77.04%, and Fusarium solani by 51.48; similarly, the IC₅₀ of antioxidant activity was estimated for ethyl acetate extract by 71.47% and n-butanol extract by 56.01%. This leads to the conclusion that Trichoderma harzianum VOCs play a significant role as an antifungal and antioxidant agent when taking into account the advantageous bioactive chemicals noted in the extracts. However, to our knowledge, this is the first study in Algeria presenting detailed phytochemical analysis and GC-MS profiling of Trichoderma harzianum for two extracts, ethyl acetate and n-butanol.

To reduce the abusive apply of artificial organic pesticides with discernment, biodegradable bio-pesticides origin from plants were used as an alternative phytosanitary method against crop pests. This experimentation allowed testing in vitro the bio-insecticidal activity of Anvillea radiata Coss and Dur (Asteraceae), endemic plant from the southeastern Algeria, against the cereal aphid Rhopalosiphum padi (Linnaeus, 1758). Three concentrations were tested (D1= 5mg/ml, D2= 2.5mg/ml and D3= 1.25mg/ml) with the butanolic and chloroformic extracts. The results showed a mortality rate of R. padi varying significantly by treatment and concentration according to the tested substances. The quantitative analysis of the two extracts shows that the crude butanolic extract is rich in polyphenols (348.935±7.456 µg EAG/mg MS) compared to the crude chloroformic extract (56.754±0.982 µg EAG/mg MS). Samely to the insecticidal effect tested, the concentration of 5 mg/ml presented an important insecticidal activity with the butanolic extract (62%) higher than the chloroformic extract (26%). Also, the lethal doses (LC50) of the crude butanolic extract were estimated by 23.07 mg/ml, 6.71 mg/ml and 5.70 mg/ml respectively after 24, 48 and 72hours of the treatment.