Curiel José Antonio, Pinto Daniela, Marzani Barbara, Filannino Pasquale, Farris Giovanni Antonio, Gobbetti Marco, Rizzello Carlo Giuseppe
Dipartimento di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari, Via G. Amendola 165/a, Bari, 70126, Italy.
Giuliani S.p.A., Milan, 20129, Italy.
Microb Cell Fact. 2015 May 7;14:67. doi: 10.1186/s12934-015-0250-4.
Myrtle (Myrtus communis L.) is a medicinal and aromatic plant belonging to Myrtaceae family, which is largely diffused in the Mediterranean areas and mainly cultivated in Tunisia and Italy. To the best of our knowledge, no studies have already considered the use of the lactic acid fermentation to enhance the functional features of M. communis. This study aimed at using a selected lactic acid bacterium for increasing the antioxidant features of myrtle berries, with the perspective of producing a functional ingredient, dietary supplement or pharmaceutical preparation. The antioxidant activity was preliminarily evaluated through in vitro assays, further confirmed through ex vivo analysis on murine fibroblasts, and the profile of phenol compounds was characterized.
Myrtle berries homogenate, containing yeast extract (0.4%, wt/vol), was fermented with Lactobacillus plantarum C2, previously selected from plant matrix. Chemically acidified homogenate, without bacterial inoculum and incubated under the same conditions, was used as the control. Compared to the control, fermented myrtle homogenate exhibited a marked antioxidant activity in vitro. The radical scavenging activity towards DPPH increased by 30%, and the inhibition of linoleic acid peroxidation was twice. The increased antioxidant activity was confirmed using Balb 3 T3 mouse fibroblasts, after inducing oxidative stress, and determining cell viability and radical scavenging activity through MTT and DCFH-DA assays, respectively. The lactic acid fermentation allowed increased concentrations of total phenols, flavonoids and anthocyanins, which were 5-10 times higher than those found for the non-fermented and chemically acidified control. As shown by HPLC analysis, the main increases were found for gallic and ellagic acids, and flavonols (myricetin and quercetin). The release of these antioxidant compounds would be strictly related to the esterase activities of L. plantarum.
The lactic acid fermentation of myrtle berries is a suitable tool for novel applications as functional food dietary supplements or pharmaceutical preparations.
香桃木（Myrtus communis L.）是一种属于桃金娘科的药用和芳香植物，在地中海地区广泛分布，主要在突尼斯和意大利种植。据我们所知，尚未有研究考虑使用乳酸发酵来增强香桃木的功能特性。本研究旨在使用一种选定的乳酸菌来提高香桃木浆果的抗氧化特性，以期生产出功能性成分、膳食补充剂或药物制剂。通过体外试验初步评估抗氧化活性，通过对小鼠成纤维细胞的体外分析进一步证实，并对酚类化合物谱进行表征。
含有酵母提取物（0.4%，重量/体积）的香桃木浆果匀浆用先前从植物基质中筛选出的植物乳杆菌C2进行发酵。将未接种细菌并在相同条件下孵育的化学酸化匀浆用作对照。与对照相比，发酵后的香桃木匀浆在体外表现出显著的抗氧化活性。对DPPH的自由基清除活性提高了30%，对亚油酸过氧化的抑制作用是对照的两倍。在诱导氧化应激后，使用Balb 3 T3小鼠成纤维细胞，分别通过MTT和DCFH-DA试验测定细胞活力和自由基清除活性，证实了抗氧化活性的提高。乳酸发酵使总酚、黄酮类化合物和花青素的浓度增加，比未发酵和化学酸化对照中的浓度高5至10倍。如HPLC分析所示，主要增加的是没食子酸、鞣花酸和黄酮醇（杨梅素和槲皮素）。这些抗氧化化合物的释放与植物乳杆菌的酯酶活性密切相关。
香桃木浆果的乳酸发酵是作为功能性食品膳食补充剂或药物制剂进行新应用的合适工具。
