Plant fungal infections are a prevalent and economically significant problem in agriculture, horticulture, and natural ecosystems (Traversari et al., 2021). These infections can lead to a range of diseases with negative consequences for agricultural output, plant health, and the environment (Fisher et al., 2020; Nazarov et al., 2020). Bioactive metabolites used in combating fungal diseases are regarded as safe, effective, and environmentally friendly (Devi et al., 2020).
Bioactive compounds found in plants, microorganisms, and animals have attracted considerable attention because of their wide antimicrobial properties. These compounds include flavonoids, phenolic acids, tannins, carotenoids, sterols, alkaloids and terpenoids (Banwo et al., 2021; Echegaray et al., 2023; Haruna & Yahaya, 2021). They are essential in biological processes, such as antioxidant, antibacterial, anticancer, and antidiabetic activities, as well as in pathogen defense (Almatroodi et al., 2020; Bourais et al., 2023). Plants produce these bioactive compounds as defense mechanisms in response to threats and stress (Aguirre-Becerra et al., 2021; Niazian & Sabbatini, 2021). Secondary metabolites such as phenolic compounds are derived from primary metabolites. These compounds are synthesized using precursors, such as amino acids, fatty acids, organic acids, nucleotides, and sugars. (Marchiosi et al., 2020; Ranner et al., 2023). Secondary metabolites undergo biogenetic processes such as shikimate, polyketide, and mevalonate pathways to form diverse phenolic structures (Fuloria et al., 2022; Magray et al., 2023). These compounds are characterized by the presence of one or more hydroxyl (–OH) groups attached to a six-carbon aromatic ring (Dikpınar & Süzgeç-Selçuk, 2020; Gulcin, 2020). Phenolic compounds are present either as unconjugated glycosides or bound to sugars, such as glucose, galactose, rhamnose, xylose, or arabinose in glycosidic forms (González-Sarrías et al., 2020). Phenolic acids, flavonoids, tannins, stilbenes, lignans, and coumarins are some examples of phenolic compounds (Mutha et al., 2021). They are principally antioxidants because of their electron-donating phenolic groups, and are present in fruits, vegetables, herbs, and medicinal plants (Chiorcea‐Paquim et al., 2020). Polyphenolic compounds are known to provide numerous health benefits and can be extracted using various methods including maceration, Soxhlet extraction, maceration, ultrasound-assisted extraction, microwave-assisted extraction, and fermentation (Jha & Sit, 2022; Manousi et al., 2019). Each technique has specific advantages and limitations that impact the characteristics and effectiveness of the extracted compounds.
Larrea tridentata is a perennial shrub that is native to the semi-desert regions of the United States and Mexico. It is also referred to as the creosote bush, and its extensive medicinal usage dates back through the histories of both nations (Lasché et al., 2023; Schwertner-Charão et al., 2022). This plant is part of the Zygophyllaceae family, which comprises approximately 30 genera and over 250 species that are predominantly discovered in warm and arid regions (Hadjadj et al., 2022; Morales-Ubaldo, Rivero-Perez, et al., 2022). L. tridentata typically grows at heights of 0.5 to 3.5 m and produces a light perfume(Bié et al., 2023). It has a spreading stem with lanceolate green-yellowish leaves, yellow blooms, and ovoid fruits with tiny white hairs enclosing black seeds(Skouta et al., 2018). This plant has gained popularity because to its apparent usefulness in resolving a wide range of health problems(Kannenberg et al., 2022). L. tridentata has long been used to treat a variety of health issues, including infertility, rheumatism, arthritis, diabetes, gallstones, kidney stones, common colds, diarrhea, skin problems, obesity, pain, and inflammation. (Morales-Ubaldo, Gonzalez-Cortazar, et al., 2022; Torres-León et al., 2023).
L. tridentata leaves have been found to have strong antifungal activity against various fungal strains, including Rhizoctonia solani. The lanolin extract showed complete inhibition of mycelia at 2000 mg/L, while cocoa butter and water extracts required 3000 and 8000 mg/L for the same inhibition(Castillo et al., 2010). L. tridentata leaves were also effective against Pythium spp., Colletotrichum truncatum, C. coccodes, Alternaria alternata, Fusarium verticillioides, F. solani, F. sambucinum, and Rhizoctonia solani (Osorio et al., 2010). According to Chavez-Soliz et al.(2014), aqueous leaf extracts of L. tridentata at concentrations of 1000 mg/L and 5000 mg/L notably reduced the severity of Podosphaera xanthii, which causes powdery melon mildew. Galvan et al. (2014) reported that an aqueous extract of L. tridentata (at concentrations of 10% and 20%) showed significant antifungal effects against Phytophthora capsici and Aspergillus flavus, achieving complete inhibition after 48, 72, and 96 h. Furthermore, the leaf extract of L. tridentata, either alone or in combination with potassium sorbate, effectively inhibited A. flavus growth under pH conditions of 3, 4, and 5, exhibiting a synergistic action when combined. (Munguía et al., 2014). Francisco et al. (2015) assessed the in vitro antifungal activity of L. tridentata water, ethanol, lanolin, and cocoa butter extracts against P. cinnamomi, the ethanol extract completely inhibited mycelium, while the lanolin extract showed very low inhibition. L. tridentata ethanol and dichloromethane extracts reduced fungal growth by 75–100% against A. tenuissima, A. niger, Penicillium polonicum, and Rhizopus oryzae. Aguirre-Joya et al. (2018) used bioactive films comprising L. tridentata polyphenols to achieve 50% inhibition of A. alternata, F. oxysporum, Botrytis cinerea, and C. gloeosporioides.
This study addressed the potential of bioactive compounds in plant defense and their biological applications by extracting antifungal polyphenolic bioactive compounds from L. tridentata stems and leaves through maceration and Soxhlet extraction, assessing the total polyphenol content and antioxidant potential, and characterizing the extracts using high-performance liquid chromatography (HPLC).