Inhibitory Effect of Cinnamaldehyde on Main Destructive Microorganisms of Nanhai No. 1 Shipwreck

Xinduo Huang,Jing Du,Jiao Pan,Peifeng Guo,Yu Wang,Yue Li,Zhiguo Zhang,Yeqing Han,Kaixuan Ma,Naisheng Li

doi:10.3390/app11115262

Abstract

Nanhai No. 1, a shipwreck in the Southern Song Dynasty, China, has a history of more than 800 years. It was salvaged in 2007 and is now on display in the Guangdong Maritime Silk Road Museum. Due to the fact that the hull is a wooden cultural relic and exposed to the air, the biological corrosion and biodegradation caused by microorganisms are key problems of hull protection. At present, the antimicrobial agent Euxyl® K100 (isothiazolinone) has a significant antimicrobial effect in the field, but it has a certain negative impact on the environment and archeologists. In order to reduce the use of chemical antimicrobial agents, we evaluated the inhibitory effects of cinnamaldehyde on the main destructive microorganisms of Nanhai No. 1. Cinnamaldehyde is the main active component of cinnamon, and has broad-spectrum antimicrobial properties. The paper diffusion method, gas diffusion method and minimum inhibitory concentration experiment were used to detect the inhibitory effects of cinnamaldehyde on the main microorganisms of Nanhai No. 1. We found that cinnamaldehyde had significant inhibitory effects on Bacillus tequilensis NK-NH5, Bacillus megaterium NK-NH10, Bacillus velezensis NK-NH11, Bacillus sp. NK-NH15, Bacillus sp. NK-NH16, Bacillus sp. NK-NH17, Fusariumsolani NK-NH1 and Scedosporiumapiospermum NK.W1-3. At the same time, cinnamaldehyde had more inhibitory effects on fungi than bacteria. Finally, we verified that cinnamaldehyde can effectively inhibit the growth of microorganisms in water, for storing the scattered wood blocks of the Nanhai No. 1 hull through laboratory simulation experiments. Cinnamaldehyde, as an environment-friendly antimicrobial agent, is of great significance to protecting water-saturated wooden relics from microbial corrosion and degradation in the future.

Highlights

Nanhai No 1, a Chinese Song Dynasty shipwreck, was discovered in 1987 near the Chuanshan archipelago in the South China Sea, Guangdong Province
The discovery of Nanhai No 1 wreck is of great significance to Chinese underwater archaeology, and provides important clues for the study of Maritime Silk Road
We found that S. apiospermum (NK.W1-3) was very sensitive to cinnamaldehyde

Summary

Introduction

Nanhai No 1, a Chinese Song Dynasty shipwreck, was discovered in 1987 near the Chuanshan archipelago in the South China Sea, Guangdong Province. In 2012, archaeological excavation was officially started [1], and a large number of precious cultural relics such as gold, silver, bronze, iron, lacquer and porcelain were found in the wreck. The discovery of Nanhai No 1 wreck is of great significance to Chinese underwater archaeology, and provides important clues for the study of Maritime Silk Road. The hull and the cultural relics of Nanhai No. are the key protected objects. With the excavation of Nanhai No., the exposed area of the hull increases gradually. Due to the high humidity and high temperature in the storage environment of Nanhai No 1, and the fact that wooden cultural relics are natural organic matter, this provides suitable conditions for the growth and reproduction of microorganisms [3].

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