DPPH Radical Scavenging Activity of New Phenolics from the Fermentation Broth of Mushroom Morehella importuna

Abstract

In recent years, wild morel mushroom species have begun to be widely cultivated in China due to their high edible and medicinal values. To parse the medicinal ingredients, we employed the technique of liquid-submerged fermentation to investigate the secondary metabolites of Morehella importuna. Two new natural isobenzofuranone derivatives (1–2) and one new orsellinaldehyde derivative (3), together with seven known compounds, including one o-orsellinaldehyde (4), phenylacetic acid (5), benzoic acid (6), 4-hydroxy-phenylacetic acid (7), 3,5-dihydroxybenzoic acid (8), N,N′-pentane-1,5-diyldiacetamide (9), and 1H-pyrrole-2-carboxylic acid (10), were obtained from the fermented broth of M. importuna. Their structures were determined according to the data of NMR, HR Q-TOF MS, IR, UV, optical activity, and single-crystal X-ray crystallography. TLC-bioautography displayed that these compounds possess significant antioxidant activity with the half DPPH free radical scavenging concentration of 1.79 (1), 4.10 (2), 4.28 (4), 2.45 (5), 4.40 (7), 1.73 (8), and 6.00 (10) mM. The experimental results would shed light on the medicinal value of M. importuna for its abundant antioxidants.

Biological Activities of Secondary Metabolites from the Edible-Medicinal Macrofungi

“…Morchella esculenta Morchellaceae 1-3 [13] Ganoderma lingzhi Ganodermataceae 4 [14] Macrolepiota procera Agaricaceae 5-16 [15] Fuscoporia torulosa Hymenochaetaceae 17-26 [16] Phellinus igniarius Polyporaceae 27-28 [17] Wolfiporia cocos Polyporaceae 29-46 [18] Ganoderma lingzhi Ganodermataceae 47 [19] Calvatia nipponica Lycoperdaceae 48-52 [20] Butyriboletus roseoflavus Boletaceae 53 [21] Ganoderma luteomarginatum Ganodermataceae 54-56 [22] Pleurotus florida Pleurotaceae 57 [23] Laetiporus sulphureus Polyporaceae 58-59 [24] Sarcosphaera crassa Pezizaceae 60-63 [25] Tricholoma ustaloides Tricholomataceae 64-65 [26] Lentinula edodes Omphalotaceae 66-68 [27] Ganoderma Ganodermataceae 69-72 [28] Ganoderma lucidum Ganodermataceae 73-75 [29] Morchella importuna Morchellaceae 76-78 [30] Oudemansiella raphanipes Tricholomataceae 79-81 [31] Sanghuangporus sanghuang Hymenochaetaceae 82-87 [32] Paxillus involutus Paxillaceae 88-93 [33] Paxillus involutus Paxillaceae 94-101 [34] Pleurotus ostreatus and Pleurotus eryngii Pleurotaceae 102-103 [35] Morehella importuna Morchellaceae 104-110 [36] Lepista sordida Tricholomataceae 111-112 [37] Poria cocos Wolf Polyporaceae 113-117 [38] Ganoderma lucidum Ganodermataceae 118 [39] Fomitopsis pinicola Coriolaceae 119-127 [40] Ganoderma orbiforme Ganodermataceae 128-129 [41] Inonotus obliquus Hymenochaetaceae 130-136 [42] Table 1. Cont.…”

“…Compound 103 (EC 50 = 573 µM) showed moderate activity against the DPPH radical [35]. Phenolic compounds (104-110) showed a DPPH radical scavenging ability, and the IC 50 value of these compounds were 1.79, 4.10, 4.28, 2.45, 4.40, 1.73, and 6.00 mM, respectively [36]. In the ABTS radical-scavenging activity test, 111 (EC 50 = 0.001 mg/mL) and 112 (EC 50 = 0.145 mg/mL) showed strong antioxidant activity compared with Vitamin C (EC 50 < 0.025 mg/mL) [37].…”

DPPH Measurements and Structure—Activity Relationship Studies on the Antioxidant Capacity of Phenols

“…Nevertheless, the DPPH assay is widely preferred because it is inexpensive, simple, and rapid [ 10 ]. Although the antioxidant capacity measurements in such in vitro studies were acknowledged to have conceptual and technical limitations [ 11 ], such studies are useful for confirming whether a compound possesses antioxidant capacity [ 12 , 13 ].…”