**2.1. Flavanoids**

*Pongamia pinnata* were rich in flavanoids compared with other semi-mangroves. Up to now, more than 50 flavaonoids have been isolated from *Pongamia pinnata* with the structural characteristic of furan or pyran ring parallelized with the skeleton of flavaonoids. Partial flavaonoids including flavone, flavonone, chalcone, dihydrochalcone were listed in Figure 3.

**Figure 2.** Pictures of 12 semi-mangroves spread in China

Natural Products from Semi–Mangrove Plants in China

http://dx.doi.org/10.5772/55933

**Figure 2.** Pictures of 12 semi-mangroves spread in China

The word's mangrove plants have 84 species (including 12 varieties) in 24 genera and 16 families. Of which, true mangrove plants have 70 species (including 12 varieties) in 16 genera and 11 families, and semi-mangrove plants 14 species in eight genera and five families [3]. 12 species of semi-mangroves were grown in China including *Barringtonia racemosa, Cerbera manghas*, *Dolichandrone spathacea*, *Pluchea indic, Hernandia nymphiifolia*, *Pongamia pinnata*, *Pemphis acidula*, *Hibiscus tiliaceus*, *Thespesia populnea*, *Premna obtusifolia*, *Clerodendrum inerme*, *Heritiera littoralis* [3]. Hainan province of China is most rich in semi-mangroves, where all of the 12 species were spread there. 8 species were grown in Guangxi province, 10 species were distributed in Taiwan province, 7 species were found in Fujian province, 7 species were grown

Most semi-mangroves possessed medicinal usages were utilized as folk medicine in many provinces of China. For example, the seeds of *Cerbera manghas* were used as emetic and purgative medicine in Hainan province [1]. The leaves and branches of *Hibiscus tiliaceus* were used as the agents of clearing heat and reducing the swelling. The crude extract of *Pongamia pinnata* can effectively inhibit pathogen of the multiple evanescent white dot syndromes, and reduce mortality. The seeds of *Barringtonia racemosa* showed anti-cancer and anti-microbial activities. *Thespesia populnea* possessing relieving pain, anti-inflammatory, anti-microbial, and antioxidant activities can also protect the liver damage induced by carbon tetrachloride.

Chemical constituents isolated form semi-mangrove plants with various and unique structures including flavanoids, lignans, sesquiterpenoids, diterpenoids, triterpenoids, steroids, and alkaloids et al. For example, Abe and coworkers obtained cardiac glycosides from the seeds of *Cerbera manghas* [4]. Alis isolated some oxygenated sesquiterpenoids from the roots of *Hibiscus tiliaceus*. Some flavanoids as glabone were isolated from *Pongamia pinnata* and Wang obtained

Meanwhile, the biological activities of the isolated compounds were studied extensively. Some were found to have obvious biological activities. For example, cardiac glycosides showed obvious anti-cancer activity[11] and bartogenic acid can inhibit the activity of α-glycosidase and

In short, semi-mangrove plants played an important role in curing disease and finding new chemical entities. We highlight that it will become more and more significant to the research and development of new drugs. In this review, chemical constituents and biological activities

*Pongamia pinnata* were rich in flavanoids compared with other semi-mangroves. Up to now, more than 50 flavaonoids have been isolated from *Pongamia pinnata* with the structural characteristic of furan or pyran ring parallelized with the skeleton of flavaonoids. Partial flavaonoids including flavone, flavonone, chalcone, dihydrochalcone were listed in Figure 3.

of semi-mangrove plants were mainly regarded and they are as follows.

in Hongkong, and 3 species were found in Macao [4].

5 thiophene derivatives from *Pluchea indic*.

**2. Chemical constituents**

amylase [13].

194 Column Chromatography

**2.1. Flavanoids**

HO <sup>H</sup> HO <sup>H</sup>

13

11 12

<sup>H</sup> OH

O

6

O

O HO O

O

H

O

13 14

2 1 <sup>3</sup> <sup>4</sup> <sup>5</sup>

11

HO

O

12

7 8 10 9

O

**Figure 5.** Structures of mansonones from *Hibiscus tiliaceus*

OH

OH

**Figure 4.** Structures of sesquiterpenoids from *Pluchea indica*

HO

HO

GlcO

1

<sup>3</sup> <sup>4</sup> <sup>5</sup>

10

14

15

O HO

OH <sup>H</sup> OH

<sup>H</sup> OH

OH

197

HO

Natural Products from Semi–Mangrove Plants in China

OH

OAc

O O

O

O HO O

O HO O

O

H

O

HO

http://dx.doi.org/10.5772/55933

O OH

OGlc

O O

O O O

O

O

OH

O

O

O

HO

O

HO

O

OH

Sesquiterpenoids isolated form *Hibiscus tiliaceus* and *Thespesia populnea* with highly oxygenated structures attracted many scientists' attention. Nine oxygenated sesquiterpenoids were

O

isolated from the heartwood of *Hibiscus tiliaceus* and they are shown in Figure 5.

O

O

O

O HO O

O

O

H

OH

<sup>H</sup> OH

HO OH

HO OH

HO

**Figure 3.** Flavonoids from *Pongamia pinnata*

### **2.2. Sesquiterpenoids**

Sesquiterpenoids isolated form *Pluchea indic*, *Hibiscus tiliaceus*, and *Thespesia populnea* were given full attention. Most sesquiterpenoids isolated form *Pluchea indic* were eudesmane and eremophilane diterpenoid skeleton, For example, the compounds were depicted in Figure 4.

**Figure 4.** Structures of sesquiterpenoids from *Pluchea indica*

O

O

O

O

O

O

H3CO

OCH3

OCH3

O

H3CO OCH3

H3CO OCH3

O

O

O

OCH3

OCH3

Sesquiterpenoids isolated form *Pluchea indic*, *Hibiscus tiliaceus*, and *Thespesia populnea* were given full attention. Most sesquiterpenoids isolated form *Pluchea indic* were eudesmane and eremophilane diterpenoid skeleton, For example, the compounds were depicted in Figure 4.

OH

O

2

1' 2' 3' 4' 5' 6'

O O

O

O

OCH3 OCH3 O O

> OCH3 OCH3

OCH3 <sup>O</sup>

OCH3

O

O

<sup>3</sup> <sup>4</sup> <sup>5</sup>

1'' 2''

196 Column Chromatography

O

O O OCH3

O

O

O

H3CO

H3CO

O

O

OCH3

O O

**Figure 3.** Flavonoids from *Pongamia pinnata*

O

**2.2. Sesquiterpenoids**

OH OCH3 <sup>O</sup>

OCH3

O

O

O

OCH3 OCH3 OCH3

OCH3

O O

O O O O

H3CO

OH O

H3CO

H3CO

O O

O O O

H3CO OCH3

O

O

<sup>O</sup> <sup>O</sup>

O

O O

OCH3 OCH3

> O O

O O

OCH3

OCH3

O

O

OH

OCH3 OCH3 <sup>O</sup>

OCH3

OH

OCH3

O

O

O

O

OCH3

OCH3

Sesquiterpenoids isolated form *Hibiscus tiliaceus* and *Thespesia populnea* with highly oxygenated structures attracted many scientists' attention. Nine oxygenated sesquiterpenoids were isolated from the heartwood of *Hibiscus tiliaceus* and they are shown in Figure 5.

**Figure 5.** Structures of mansonones from *Hibiscus tiliaceus*
