Medicinal Plants and Mushrooms of Yunnan Province of China

Clara Bik-San Lau, Chun-lin Long, Clara Bik-San Lau, Chun-lin Long

• Publisher: CRC Press
• Year: 2021
• Print ISBN: 9781032023380
• eBook ISBN: 9781000403657
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Biochemistry in Medicine
• Index: Biological Sciences

Although many texts describe plants from China, the focus of this book is to draw on the rich culture and environment of medicinal plants and fungi/mushrooms of Yunnan Province. In fact, Yunnan Province covers two global hotspots of biodiversity, with the richest biological and cultural diversity in China. In particular, the Kunming Institute of Botany (KIB) of the Chinese Academy of Sciences (founded in 1938 and located in the capital city of Yunnan Province) has made great contributions in the fields of botany and phytochemistry, earning an international reputation. This book covers those medicinal plants and fungi/mushrooms specific to Yunnan Province, and is written mainly by KIB experts in this research field.

Key Features:

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• Distinct sections cover the breadth of the topic including resource availability (wildly grown or cultivated), sustainability, and distribution

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• Discusses plant parts used for medicinal uses (the folklore, the ancient and modern uses)

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• Describes the important natural products and the known pharmacologically active components

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• Presents biological activities related to medicinal uses or clinical evidence

Cover image: Shilin, the stone forest (eroded vertical pinnacles of limestone), landmark of Kunming, Yunnan.

Section 1

Medicinal Plants for Drug Development

1
Diterpenoids of Isodon Species in Yunnan Province

Kun Hu,^* Jia-Meng Dai,* Han-Dong Sun, and Pema-Tenzin Puno^†
State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, People’s Republic of China

* These authors contributed equally to this work.

† Corresponding author.

Contents

1.1 Introduction

1.2 Research on Isodon eriocalyx

1.2.1 Research on Eriocalyxin B

1.2.2 Research on Maoecrystal V

1.2.3 Research on Other Diterpenoids from I. eriocalyx

1.2.3.1 Maoecrystal Z (3)

1.2.3.2 Laxiflorolides A (4) and B (5)

1.2.3.3 Neolaxiflorins A (6) and B (7)

1.2.3.4 Laxiflorol A (8)

1.2.3.5 Maoeriocalysins A–D

1.3 Research on Isodon scoparius

1.3.1 Research on ent-Clerodanoids from I. scoparius

1.3.2 Research on ent-Halimanoids from I. scoparius

1.3.3 Research on Meroditerpenoids from I. scoparius

1.3.4 Research on ent-Kauranoids from I. scoparius

1.4 Research on Other Isodon Species

1.4.1 I. Adenanthus

1.4.2 I. Ternifolius

1.4.3 I. Xerophilus

1.4.4 I. Phyllostachys

1.4.5 I. Hispida

1.5 Study of Endophytic Fungi from Isodon Species

1.6 Summary and Outlook

References

1.1 Introduction

Isodon (Labiatae; synonyms: Plectranthus, Rabdosia, etc.) is a plant genus containing approximately 150 species worldwide, which are mainly distributed in tropical and subtropical Asia (Figure 1.1) (Li and Hedge, 1994). Many Isodon species are used as important folk medicines, for example, in Henan province, China, I. rubescens (dong ling cao) is often used to treat esophageal cancer; while in Japan, the leaves of I. japonica and I. trichocarpa (enmei-so) are often used to treat gastrointestinal dysfunction (Fujita and Node, 1984). Modern phytochemical research on Isodon species was initiated in the 1910s in Japan (Yagi, 1910), and a milestone came when enmein was isolated from enmei-so in 1958 and was finally identified as a 6,7-seco-ent-kaurane diterpenoid in 1964 (Litake and Natsume, 1964). In China, phytochemical research on Isodon species began in the 1970s with the purpose of finding the constituents responsible for the anti-cancer bioactivity of I. rubescens. Over the past few decades, extensive research on Isodon species has demonstrated many of these species to be a “gold-mine” of structurally diverse and biologically fascinating diterpenoids, with ent-kaurane and its derivatives being the dominant members. So far, over 1200 diterpenoids have been isolated and identified from this genus and over 900 have been reported by our research group. The structures, classifications, and plausible biogenetic pathways of diterpenoids from Isodon species have been comprehensively presented in two reviews by our group (Sun et al., 2006, Liu et al., 2017), and this chapter builds and expands on this ongoing research. The intriguing structures of these diterpenoids have aroused great interest among synthetic organic chemists, and the total syntheses of nearly 20 of them have been completed (Yan et al., 2018, Li et al., 2019a). For example, total synthesis of oridonin has been achieved by Luo’s group recently (Kong et al., 2019). Furthermore, the various bioactivities of these diterpenoids, especially their desirable anti-cancer activities, make them highly appealing to pharmacologists, and the mechanism of action (MOA) of some of them has been clarified (Sun et al., 2006, Liu et al., 2017, Sarwar et al., 2020). For example, parvifoline AA was recently identified as an inhibitor of peroxiredoxins and a potential immune therapeutic agent (Zhu et al., 2019).

FIGURE 1.1 Some Isodon species distributed in China (photos by Pema-Tenzin Puno).

Yunnan Province possesses abundant resources of Isodon plants with an estimated 49 species identified. The medicinal value of many Isodon species, for example, I. eriocalyx, I. scoparius, I. adenantha, etc., in anti-infection, anti-inflammation, anti-cancer, etc., properties has long been recognized and employed by local inhabitants. Great efforts have been made to explore the phytochemistry of Isodon species grown in Yunnan Province, and a series of structurally and biologically interesting molecules has been discovered (Figures 1.2, 1.4, and 1.5; Table 1.1). For example, maoecrystal V was identified as one of the most structurally complex members within ent-kauranes (Li et al., 2004), and its total synthesis has been completed in a few laboratories (Smith and Njardarson, 2018). Eriocalyxin B has received considerable attention due to its remarkable anti-tumor property and its extensively studied MOA; thus, it was considered as an important anti-tumor lead compound (Riaz et al., 2019). In this chapter, we will introduce the research on diterpenoids of Isodon species in Yunnan Province, mainly concerning their structures, bioactivities, pharmacological mechanisms, and chemical syntheses. The research on several important species, including I. eriocalyx, I. scoparius, etc., as well as a few important molecules, including maoecrystal V, eriocalyxin B, etc., will be highlighted. Furthermore, in the past few years, interesting results have been obtained in our research on endophytes of Isodon species, and they will be briefly introduced in this chapter.

FIGURE 1.2 Representative diterpenoids from I. eriocalyx.

TABLE 1.1
Anti-Tumor Activities of ent-Kauranoids from Isodon Species Distributed in Yunnan

Compounds	Tumor Cell Lines	Activity (IC50, μM)	Species	References
Eriocalyxin B	HL-60	0.87	I. eriocalyx	Shen et al., 2005
Laxiflorin J	T24	0.86	I. eriocalyx	Niu et al., 2002b
Laxiflorin E	K562	0.22	I. eriocalyx var. laxiflora	Niu et al., 2002a
Laxiflorin C	K562	0.57	I. eriocalyx	Li et al., 2004
Maoecrystal P	HL-60	1.00	I. eriocalyx	Wang et al., 2012b
Laxiflorin B	HL-60	0.80	I. eriocalyx var. laxiflora	Wang et al., 2014
	SMMC-7721	1.00
	SW480	0.60
Neolaxiflorin P	HL-60	0.95	I. eriocalyx var. laxiflora	Wang et al., 2015a
	SMMC-7721	0.69
	MCF-7	0.83
	SW480	0.45
3-epi-Isodopharicin A	HL-60	1.00	I. scoparius	Jiang et al., 2017
	SW480	0.90
Isoscoparin L	NB4	0.70	I. scoparius	Zhao et al., 2009
Xerophinoid B	K562	0.32	I. xerophilus	Weng et al., 2007
Xerophilusin I	HL-60	0.19	I. xerophilus	Hou et al., 2001
	MKN-28	0.07
Xerophilusin I	K562	0.04	I. xerophilus	Li et al., 2007
	HepG2	0.19
Xerophilusin II	K562	1.00	I. xerophilus	Li et al., 2007
Isowikstroemin A	A-549	0.88	I. wikstroemioides	Wu et al., 2014a
Wikstroemioidin G	SW480	0.90	I. wikstroemioides	Wu et al., 2014b
Wikstroemioidin P	SMMC-7721	0.80	I. wikstr...

Table of contents

• Cover
• Half-Title
• Series
• Title
• Copyright
• Contents
• Foreword
• Preface
• Acknowledgments
• About the Editors
• Editors and Corresponding Authors Information
• Section 1 Medicinal Plants for Drug Development
• Section 2 Medicinal Mushrooms and Fungi
• Section 3 Plants as Health Food or Supplements
• Section 4 Medicinal Plants among Ethnic Groups
• Index